I hunted in Europe and was properly licensed, without that license the US Fish and Wildlife will not give you an import permit, and if you try and bring something in without it you get to go to gay-love (albeit against your will) federal prison.
One of the guys I work with has a cheetah skin from one he shot in Namibia in 2000. He has been working overseas all over the world and so far has not entered the United States with it. I keep telling him it is a bad idea to try and bring it back when he retires, but so far he's still overseas and doesn't have to worry about it.
Really BS what the USFWS can get away with in prosecuting you. If you get a speeding ticket in Namiba while you are there no problem, but if you break a wildlife law you can be tried in the United States.