I haven't had much time lately to answer questions with the second shotgun season in full swing.
Up until two (?) years ago it was illegal to have a full skull plate in your possession that you had found. The main reason for this (my opinion) was to preclude someone from killing a nice buck, "hiding" the rack for awhile for it to get bug eaten or whatever, and then "discovering" it. Granted it wouldn't be eligible for P&Y, but it would be for B&C as they accept pick ups, or for someone to sell it.
As for the legality of legally possessing sheds and not full skulls (before the change) think about it for a minute. With sheds you know the deer was alive when he lost the antlers. The above paragraph explains why (IMO) it was illegal to possess full skulls.
But the rule has changed and if you come across one out of a season, and your local Conservation Officer can determine that nothing illegal was involved it is yours to keep.
If you come across a dead deer with a nice rack during a season (bow, shotgun or muzzleloader) if you want the deer you will have to use your tag.
Road kills, as mentioned above, go first to the person who hit the deer, then if they don't want it, and some else present does, they can have it. Road kill salvage tags are for the whole deer, not just the rack.
Doug Clayton
State Conservation Officer