Apparently some people have problems with the surface of the rubber grip coming off:
D300 Rubber grip Part# IF998-380 $17.05
Nikon Parts Dept. 1-310-414-8107 7am-3pm PT
This information comes from here, where it also was stated that “a screw in the battery compartment needs to be removed” as you attempt to replace the rubber.
pH³ 
2010-09-08 (Wednesday, week 36) at 18:45
The Video, USB, and power rubber-flap door:
The rubber door to the connector compartment eventually wears out along the edges.
This leads to “impossible” problems with keeping it closed.
The problem is: Wear-out at the INNER edge of the flap.
Opinion:
The choice of material here is suboptimal. Alternatively another type of flap/hatch should have been used.
Makeshift solution: Use VERY FINE side cutters, as those used for the pins of electronics components (cost €20), and CUT TINY-TINY pieces along the edges until you get an egde that suits the compartment and IS PERPENDICULAR to the outer side of the flap.
There really is no other VIABLE solution than replacement, which will eventually wear out again.
2010-09-08 (Wednesday, week 36) at 21:43
ref parts 1K660-330 aka IF LID
NikonUSA’s parts department:
Phone: 1-310-414-8107
Fax: 1-310-322-6979
7am – 3pm PST Mon – Fri
Info source: http://nikonrumors.com/forum/topic.php?id=1181
Google(+D300 +rubber +door +replace -memory +nikon)
2011-02-16 (Wednesday, week 07) at 20:18
Seems my makeshift fix is just that; makeshift…
I have an escalating problem keeping the door closed.
2011-01-21 (Friday, week 03) at 18:39
Battery doors
Rubber parts, e.g. Bottom Terminal Cover (covers D300 bottom terminal, the on used for e.g. MB-D10 battery grip)
Dual terminal cover
Jack cover
– http://www.bocaphoto.com/products/new/nikon/nikonparts.htm
Batteries and Chargers
Books and Videos
Cables and Remotes
Caps and Covers
Cases and Straps
Cleaning Supplies
Flash Accessories
General Accessories
Lens Hoods
Viewfinder Accessories
– http://www.bocaphoto.com/products/new/nikon/nikonacc.htm
2011-01-21 (Friday, week 03) at 19:04
Nikon UK:
http://www.europe-nikon.com/en_GB/service_support/Repair+Centre/Support_Spares.page?lid=8&lidsub1=0&lidsub2=0&lidsub3=0&lidsub4=0&sParamValueLbl=&sParamValue=&dcr=
2011-01-21 (Friday, week 03) at 19:05
Nikon USA:
http://www.nikonusa.com/Service-And-Support/Service-And-Repair.page
2011-01-21 (Friday, week 03) at 19:08
http://www.google.se/#hl=sv&source=hp&biw=1276&bih=804&q=Repair+Parts+for+Nikon&fp=1&cad=b
2011-02-27 (Sunday, week 08) at 15:52
Some price examples:
http://www.flickr.com/groups/nikon_d300_users/discuss/72157624281780260/72157626128194962/
2011-02-27 (Sunday, week 08) at 15:56
Hrm? D40x repair:
2011-07-27 (Wednesday, week 30) at 20:46
These tiny screws (Phillips “+” head #0 screwdriver shown) hold the IF compartment lid in place:
One can access them by simply moving away the rubber in front of the attachment:
On my D300 there was hardly any glue at the edge, for the time being it stays closed after this operatione. The cost for the rubber lid was 12€ including shipping.
I take the replacement lid to be more “plastic” than the original – a simple push closes it.
This was never the case with the original.
2011-08-04 (Thursday, week 31) at 20:13
Having had a better look on the front rubber…
it is mounted with double sided tape, http://en.wikipedia.org/wiki/Double-sided_tape .
I replaced enough of it to have the rubber piece stay in place.
2011-10-29 (Saturday, week 43) at 21:02
Fooled, it doesn’t stay in place… have tried several brands of double sided tape, and some other stuff… the thing that DOES keep it in place is duct tape.
2013-09-21 (Saturday, week 38) at 14:47
NOTE: The rubber pieces comes from Nikon with double sided tape, you just have to ply off a paper cover and stick the rubber in place. No glue.
2012-02-11 (Saturday, week 06) at 16:28
I have tried yet another way to accomplish a neat and tidy rubber side along the flap – here are the tools:
… somehow I think I succeeded now. The rubber still holds in place, dispite the camera having being in use for one evening.
2012-02-11 (Saturday, week 06) at 16:38
1a. Make sure you can mount the rubber in an instant, practice
1b. Make sure you have an easy way to fixate the rubber cover as it has glue attached.
2. Clean, clean and clean – and make sure it is real clean.
3. Pour out a limited amount of the glue on e.g. a cardboard covered with paper.
4. Use toothpicks to place small amounts of glue onto the surface just beside the openings for the flap screws. BE VERY SURE to not have the glue end up inside the camera (through the holes!).
Too much glue will inevitably end up in the wrong place!
5. Mount the rubber cover.
6. Make sure to fixate it in place… the above glue needs 24h+ to harden.
The broad tape shown seems to be a nice way to have stay fairly stationary, but in my opinion a ‘perfect’ result requires more than so. Maybe a weight of appropriate size and shape.
2012-04-08 (Sunday, week 14) at 17:40
Similar description as above:
http://www.mark4pics.com/Gear/D300-Repairs/20054597_BZH295
Link found here, which has some mumbo-jumbo.
http://www.flickr.com/groups/nikon_d300_users/discuss/72157627629543393/
2012-05-24 (Thursday, week 21) at 20:59
D700
Not yet read this, just saving it here:
http://forums.dpreview.com/forums/read.asp?forum=1039&message=19461381
http://www.flickr.com/groups/nikond700/discuss/72157621848951850/72157625050614185/
http://www.amazon.com/3M-08008-Black-Weatherstrip-Adhesive/dp/B00063X38M
http://forums.dpreview.com/forums/readflat.asp?forum=1021&message=32714580&changemode=1
2012-07-24 (Tuesday, week 30) at 12:59
More cheap stuff, even CHIPS (look for “Dandelion chip”) that suit old lenses – for metering to work on new camera bodies
http://store.tagotech.com
2013-02-25 (Monday, week 09) at 19:16
D700 Rubber
http://www.flickr.com/groups/nikond700/discuss/72157627119029799/72157632842780817/
2016-02-20 (Saturday, week 07) at 16:07
https://www.flickr.com/groups/nikond700/discuss/72157621848951850/
2016-06-18 (Saturday, week 24) at 09:34
A simple note after a long silence on this:
The INTERFACE rubber door is the hard part, maybe that the right hand front rubber has a screw to undo (inside the battery compartment (I haven’t replaced
that yet), the remaining parts though are double-side-tape type of fastening only.