GM factory mistake, 350 Vet motor in my 72.

[EZTHERE]

I just bought a 72 GMC Jimmy from an impound lot. After chatting with the original owner. He tells me the truck had lots of power. So when he looked at the front pad serial numbers he couldnt find them after he talked with the dealer. It turns out to be a factory mistake. GM installed a 350 vet motor. Per GM. I have not varified this yet.

Has anyone ever heard of that before??

does this make this a rare truck or an odd ball. Im thinking odd ball.