I would definitely not raise, Id say this is 65% toward someone trying to get 3 streets of value where he thinks you might check behind on turn and 35% random bluff from villain. Either case call and see what he does on the river. Reads are really nice though in these spots. Against some villains I'd muck right there; other fish you can raise here because they are just taking random stabs and don't fold. But calling is the play vs. unknown.