Culture and everyone else is right there would be
no mint surface on coins in that grade. Obviously no one can say anything to convince you otherwise so I agree it's time to send the coin in and see for yourself. Hopefully after sending it to PCGS then cracking it out and sending it to NGC then cracking it and sending it to ANACS/ICG that will be enough proof for you that it isn't that coin. The real hope would be to save the money on those fees but no ones going to convince you.
I would bet if you started asking around with dealers or some of the heavyweights someone would have knowledge where the original coin is.