I think in most states the law says tag it first. It also makes sense in terms of not getting the license or tag all messed up by bloody hands.

Pa law says immediately. Had a problem years back with a local cop when Pa law said "tag immediately after removing entrails but before moving the animal" The local Barney Fife gave mea hard time for gutting (but not moving it) first. Now I always tag it before I do anything else.