It matters to WHOM you are sending the coin to as well as the coin that you have there. Obviously if you send it to SGS, it's an automatic MS70. I can even label it MS71 if you like.
I don't belive a coin can ever grade MS70/PF70 enen if it is from a proof set or mint set. How can a coin be romved from a froof set without ever touching the proof set holder and getting even a very minute scrath.
Depends on your proof set, and how you do it. But I don't argue you one bit. It seems impossible, but I guess it happens. Phoenix