You could well be right, but you say 'most'
and that refers of course to the earlier issues. These were supposedly c1975, right about the time it changed.
The insert shapes is only an indication of when Burt Co changed them, not the PS buy out of CJ.
I prefer to look at the size of the outermost 'ring' and dont find any PS LCV chips with ring that width for many years more.
Real hard to tell some of these without the chip in hand.