If you're interested in it, ask for some detailed measurements and weight, and give it a shot. It's only $45 USD, why the hell not? If it turns out to be junk, donate it to a bike rescue place or something like it.
Unless of course you don't have $45 to blow, then stay away I suppose.
The "prototype" mention makes me wonder if the frame was even heat-treated. There was an Interbike incident a few years ago where Haro had some proto frames stolen from the venue -- they were non-heat-treated, just for display, there was some caution out there for a while.
was thinking of changing this forum to a general purpose forum for unknown frames, so anyone can upload pictures or a link to unknown frames and advise others.... is it possible to change the forum title/description now that its already begun? (im new)