Here we go. I may be mistaked but I will double check when I get home.
I think my newest M60 with a SN#00xxxxxx which would be a 2000 date of manu. gun has REP encircled on the right side of the bbl. There wasn't a JM that I could see. I'll check that and get back to you. I don't have any issues with the rifle but am interested in knowing what's what.