I would be checking out the barrels, restore them, then work on all of the metal parts, get them in shape, and only then think about the buttstock. Depending on how the metal parts come out, only then think about the stock and forearm. It could be a pretty nice restoration, but you won't know until the very end. Step one is to disassemble the gun and burn the buttstock so you won't be tempted to use it. The forearm is an easy fix. Don't burn that. Join the PGCA so you can get a letter on the gun for $40.00. A heavy ten gauge Grade 3 is often ordered by a famous shooter or at least a competition shooter of note. Post your letter on this site so we can help you to identify the original owner.