In the case of NGC, they will give you "temporary" ownership credit and they will contact the current customer listed for the coin. I've had it happen a couple times. I did nothing but wait for NGC to change ownership of the coin in their system.
Thanks, the coin is a 1917 Canadian Half MS62 which only showed the 10..demand for the coin will still determine the value...
If you are looking at the NGC census, no coin will be listed with the XX/XX designation. Just look at the higher grade pops and do the math. The XX/XX designation is most only used by sellers in their listings.