Recall that DCM began selling NMs in very late 1955, but not many, and most were left over in inventory. Heavy mail order sales began in 1956 with the stated objective "every effort will be made to provide a new rifle." Some of the leftover 1955s were rebuilt and upgraded but a significant number remained in inventory as school rifles and loaners until 1974 when they were given to Greece. Most were well used by the Greeks, but I saw a couple of beauties that looked original while doing research at CMPicon several years ago. The problem with the Greek NMs, of course, is that there is no DCM documentation and never will be. CMP documentation is visual speculation: they look like NMs, we gave Greece NMs, therefore it is an NM.
On the other hand, I have always said that in the absence of documentation, an NM rifle must stand on its own. If it is minty and has "that look," it probably is an NM.