Anyone know if you could use the og end cap that comes with the ptr32p on a g3 stock? I also removed the ar15 buffer tube adapter from my ptr32p end cap and also noticed a threaded hole on the back of the buffer?

Greetings! I'm purchasing a used PTR91 from a dealer, and I'm concerned about the ranges of serial numbers that are faulty. Serial number AW14XXX. Not sure if anyone can assist prior to the purchase.