Since I accidentally double posted my reply, I may as well edit the second one to add something. I know these older Dahons only by their reputation, which is not all that great. Some people do restore them, though, and claim to be satisfied with them. You may also want to ask on the Dahon forum, where there's at least one regular poster who rides a fixed up "classic" Dahon.

http://www.dahon.com/forum/index.php