Would the C6OA-A part be a assembly line part ?
Yes, for 66 and up, but it is stamped C6OA-18832-A in a semi-circle on the top, Autolite in a straight line in the middle, and 648 curved on the bottom. There is also another condenser, part number C3SA-18832-A, that I found that might have "snuck" in on some alternators. The part number is in a semi-circle on the top and 648 in an oval in the center, no other markings, same physical size, same mounting.
Jim