Yeah, I have so many old cameras that sticky light seals is sort of the norm. In the case of most SLRs it's pretty straightforward to repair everything with medium weight black yarn in the door channels and cut pieces of adhesive backed black felt to seal the sides of the doors and create new mirror bumpers.
Probably not the professional way to do things, but I'm still using the same piece of 12x12" black felt I bought three years ago and the same little ball of black yarn.
All you need is lighter fluid, q-tips, toothpicks, and patience.
The original goo makes a really good glue to hold in the yarn 😉