It's for owning the game as opposed to playing through F2P. However, I don't know if it's given to people if they bought after UC3 went F2P or if they hadn't played UC3 recently when it went F2P.
If you PLAYED the game before 1.17 you get it. You can play on disk and you will not get paw. If you made your guy AFTER 1.17
Technically speaking, yes. But there was no magic property about 1.17 which made it special. The purpose of the paw was to show who owned the game and who didn't. It's just not retroactive, but that doesn't make playing 1.17 special inheritantly.