Dave,
I faced the same problem when repainting my car, nothing was worth using. I used the original born with gaskets that were still on my tail lights when they were removed, needless to say they fit and looked perfect. IMO there is nothing worse than seening a otherwise nice car with gaskets hanging out of the door handles, mirrors, side markers and tail lights, but it is so common. BTW there was nothing holding the gaskets, they seprate from both the car and the housing without damage. I never split the tail light housings. Hope you still have the originals to use.
Good luck,
VT