I recently discovered two Buffalo nickels that exhibit clear date and other obverse doubling. Neither coin is mentioned in any reference works that I have found. I am considering submitting both for slabbing but learned that NGC only validates and grades those from their list of acknowledged errors and variants. It was unclear of the source(s) of this list and wonder who is the final arbiter when it comes to validating "outliers." Am I mistaken about NGC limitations? If not, can someone please point me to the final authority for newly discovered mint errors and variants? My thanks in advance!