I have caught the rare stocked trout that looks like that in water that I know doesn't contain wild fish. That being said, I think I agree with Trout 2003... could be wild, could be fingerling or coop stock. Too close to call IMO. It isn't uncommon for fingerling trout to keep their parr marks on up to the size you have there - there are waters I fish that are fingerling stocked where every rainbow that comes to hand still has them at that size. Definitely a pretty little trout!
A bad day hunting rabbits beats a good day of anything else!