\'73-75 or 76 owners (fiberglas top question) Anyone out there replaced the rear (rolling) window seal in the topper? I just got the one I bought from LMC (only $50, GM doesn't sell them anymore) and after looking at it, and my late 70's and early-mid 80's topper's, realized there might be yet another top difference between the years. The LMC catalog shows a different picture of this seal for the earlier trucks, then another picture post '75 or 76, and although the seal part # is the same, the picture of it is different between the two pics. (although from pulling my original seal, I know the shape is the same, which the LMC catalog doesn't reflect) The only other difference I see (besides their misprint of the gasket shape), is that my toppers don't use the plastic push in retainer shown (and used?) in the earlier trucks canopy. For those that don't have an LMC catalog, on the '73-'75 or 76 K5 weatherstripping page, LMC shows a plastic push in retainer that is pushed into the fiberglass, on either side of the gasket, down almost at the bottom of either side, where the topper meets the tailgate. This "retainer" is cast into the rubber gasket, so you can't just remove it from the gasket without cutting it off (in my case) and it is the same style used to retain the door panels: plastic plug with "teeth" cast into it, to keep it from pulling back out once installed. I guess I'm just curious if it was simply something GM discontinued later on, that I'd be fine cutting off. I know though, that if I cut that thing off, then try to fit the gasket to the topper, and for some other reason it doesn't fit my top, (like its a poor copy or something similar) when I try to return it, they *might* hassle me for "modifying" it.