I'd agree I don't see any reason that you can't give him the rack.As far as the tag goes ,I'm sure your not expected to keep the tag on the rack after it's been processed,so there's no reason not to keep it, or give it to the kid who shot it . I'm not sure of your reg's ,but this could have been hit by a car as well, and I'm sure you wouldn't be expected to put a tag on a road kill. If your unsure maybe give your local ministry a call and ask .
It's too bad you never found him ,but sometime's these thing's happen.

nubo