I'm getting some guns from an estate, and looking at the list I find a Yugo SKS with serial number 596605xxx.

Does the 5966 leader on the number mean it's a M59/66? Or could it be a coincidence on an M59?

For anyone who was interested, the serial number on the list was one applied to the rifle at import. It is a 59/66 and it would seem that that is reflected in the import serial number.