I do not often look at eBay postings for several reasons. Most important, I don't need any more tools (yeah, right) nor do I have room to store 'em (true). But every once in awhile I'll have a little morning coffee time and I will take a look. It can be interesting.
Today I put in the search box "used woodworking hand tools buy it now" and on the third page was a listing for a "user grade" Stanley 3C seller typed as a Type 12. From the photos I couldn't see anything that would make me question the Type. The plane had been buffed and cleaned up with some evidence of deeper rust but not much, all in all I would agree the plane would make a nice $40 to $50 USD user plane except for the "C".
The seller had the plane priced at $340 USD and, at least for me, what was even more head slapping was there were 60+ following the listing. The only thing I can think of to cause that many to follow would be just wanting to see if someone would really pay $340 USD for a user grade #3C.