@UngulateNerd92 If it was, I would either be the first to get it or it would be a major buzz on the Zoo's membership page to some extent. I wouldn't be surprised if it's currently in the office where the exhibits are designed - they keep all sorts of old posters, maps and other archives in there. It wasn't even my department but it was the best place to be when I was on the clock. Speaking of signage that's no longer public - next to that same building is a dumpster, and on one of my last days as a zoo employee I noticed it was overflowing with Rhino Reserve's old signs. I missed the opportunity to snag a large information board on the okapi.
EDIT - As I'm rambling and typing all this, I found it!
@Moebelle thank you for sharing this with me. This poster is actually hanging in one of the hoofstock keeper shacks at the Los Angeles Zoo. When I used to be an animal care volunteer there, I ate my lunch in that office while viewing that poster. I have retrieved a few posters from trash cans and hung them in my apartment. Aas the old saying goes, one man's trash is another man's treasure.