The 89 set is the only UD set I have. I am no expert on UD, but the guy who started the prior thread I posted above has posted some of the rarest stuff I have seen on the board, mostly Topps though. I would take chance at the right price. Even if fake the fact there are others make it an interesting piece.
The SCD Standard Catalog has at least two Topps listings I know of that are designated as fakes and still get a listing
Reminds me some of cards discussed in this thread
http://www.net54baseball.com/showthread.php?t=191504