In case I was being too subtle, I think this one Pavcraz was selling could very well have been signed, but it could be NM+ from where the tiny signature was buffed off.
The marble is the right size for Mark Christensen's and the seller is known from the past to buy Mark Christensen marbles and present them as antique.
Of course he has also sold Fisher marbles in "vintage" lots so maybe, but this one looks like Mark C's recent offerings to me.
Are Kelly Schmidt marbles still available? Pavcraz does a pretty quick turn around business. Buys dug Akros one week and has them in his forged packaging the next. Not saying he wouldn't use older contemps if he could get his hands on them, but just thinking of availability.
Next question: who makes guineas?
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=130350655669