Trent over at the KnK Alehouse is the only guy I know who has the original module, and has run it several times.
I posed this question to him, and here's an interesting response:
T. Foster wrote:I never sent in that SASE (and even if I had I'm not sure I would've gotten a response) so I don't know, but when I've run the module I've made them Nolzur's Marvelous Pigments which seems like a pretty obvious choice (and may even be what was originally intended).
--Ron--