Hi Craig, I was originally going to do the edges of the light covers & rear window in body colour, but when I thought about the hassles of masking / priming / 2-pack painting, I decided to try just putting a very soft closed-cell foam strip (peel-off sticky-back) around the recesses in the body.
Initially, I put one thin strip each side of the bolt-holes (see pic of light covers), but later changed the rear window setup to a single strip with holes punched for the bolts (second pic). Next time I remove the light covers, I'll replace the rubber with the wider single strip + punched holes.
Note - the pics are not too good - they seem to show the rubber as being a brown colour (flash problem) - they are dead flat black.
The rubber I used was from "Farnell" here in Sydney - the part # for the thinner 5mm strip is 536-799, but I don't have a record of the part # for the wider strip (about 12mm). It is so soft that it compresses down to almost nothing (from an original thickness of 3mm).
The only trick that I later found was to soak the top surface of the rubber (once installed) with silicone spray - that stopped it from from sticking to the perspex.
You will definitely need some form of "gasket" under the perspex edges to stop crap & water - this stuff does the job, and the black colour is not all that noticeable as it provides a matt finish, rather than the super-shiny "in your face" finish that paint under the perspex will give you.
Hope this helps a bit.
Kind Regards,
Peter D.