I believe you should be able to see a stamped "L" on the end of each stud, if they are left. If not, there may be an "R" or nothing. As for the year, I believe 70 and later had all Rights. M2CsW.
This may sound like sour grapes - but he put me on the trailer in the finals last Saturday with a .021/.5021 light. Now that may not be great in Pro, but with a bunch of first timers like Dave and I who run full out and screw the mind games, unless us rookies can cut a better light than that...