Is it ever explicitely said that it's felt? Maybe it's just green paint. Or maybe it's green metal that stains as opposed to scratches, so that all anyone has to do is wipe off the table after a game with Hobbes rather than refelt/repaint it.
I hate to sound contrarian, but I won't consider Wing Commander II canon until this is explained. Why is it that in this game alone, poker tables have regenerating felt? I'm chalking it up as taking place in an alternate universe.