Thanks for the suggestion Jeff. In some further looking I found C8ZE-K1 8DB on the one without the W MO.
Per the 428CJ forum and as noted below would indicate a Dearborn car (which matches my X code, would the K1 be correct for a 68 X code? Could find no specific refs to this number. As an April 2nd week radiator date it could align to the mid May build car.)
They also note "W MO" (no other markings found, but a tag with "005258 Winchester Rad", which I am thinking is probably a recore tag from a shop) is commonly a San Jose, again as noted below, which could be from one of my two SJ S codes. Did not label them, but think it came out of my convertible long ago.