I have heard that they are and $75 seems in line with a name brand used bike that may be from the 80's or very early 90's. Based on its condition, go for it. But if its beat up, or the parts are in bad shape, I wouldn't pay over $35. Your just going to have to tear it apart and start building it with new stuff.....you already know all this anyway....
Upload some pics of the bike if you don't mind and the name and I will help you track down its history and any details on age or rebuilding details.....
This could be like a project that doesn't cost me anything...