As said above, you won't get any noticable change in accuracy. The design of the rifle isn't going to benefit you from glass bedding. And depending on the glass bedding used and stock prep, will depend on what might stick to the poly stock, I doubt you would get anything to stick that wouldn't come loose when the gun was fired.
If you want to glass bed something that will give you some experience and be fun and also make you a great cheap rifle, buy yourself a surplus Mauser.
If you just HAVE to glass bed a SKS, pick up a surplus wood stock,
KITS??? Brownells Accura Glass
good luck and have fun........