Well, there was a related thread about what the appropriate course of action is in this type of scenario would be and I believe they should have a chance to make it right. I can tell you what I'd do if I owned the rifle company. I'd send you the tan & black stock and tell you to just keep the other one for your trouble. It just plain makes business sense. They might be out a few hundred bucks (if that) and you would be happy and tell every body about it. Win-Win.
I agree with you YZ, get the other stock and call it even or they pay to ship the other one back.