I'm not aware they faked Zähringer Lions. But faked almost anything else...
Easy to recognize if you know them, impossible to if you are not aware. Unfortunally I've no pictures handy. BDOS (German medal collector siciety) has a magazine in which those fakes were shown and explained over the years very well. You'll find dozens of articles on this very issue there - unfortunally in German and mostly, back in the 90s, with rather bad pictures.
Andreas Thies e.g. somtimes offers some of these fakes - as fakes. His catalogues are online available as pdf files on his site.