Don't know that you'll find a seatbelt in a junkyard that you can scabbage. They have an explosive pre-tensioner in them and IIRC, you can't install them yourself. Hopefully, I'm wrong for the OP's sake, but if memory serves, this has come up before with the same answer.

So where does that leave you? Stealership for a new one IF you decide to replace it.

The bigger question is, how bad is the "chewing"?

-G