@Chlidonias I had never heard of "Opus the Penguin" before I saw this case. I agree, it does look weird. The mounted rooster that is supposed to be behind Foghorn Leghorn is "in preparation". I think that the curators wanted to put emphasis on the actual characters instead of the mounts by having mostly study skins in this case. It's a great space saving technique so maybe that's why they chose this style of preparation for this individual case.
I googled Opus the Penguin. I have seen a picture of the cartoon before somewhere (it looks vaguely familiar). I haven't seen the stuffed toy though - it isn't very penguin-like.