I don't see how they could hold you to a receipt for a product recall. I suppose they might ask who the retailer was, but we're all old feckers, aren't we?
Funnily enough, I just fitted a new pair this afternoon. My old pair were the gold colour ones but if I was going to have them again they'd have to be black for my TB. Two days in Wales this week was enough to remind me why I once had them fitted (joints were beginning to suffer). As has been posted, you'll know you got the modified versions as they come with two adjustment holes, not three.
PS, I assume the offer must include aftermarket, not just optioned items.