IDing My K6 Block

I was considering starting a thread to find the earliest known A-body VIN-stamped block, & earliest overall C-P-D one(s), it would turn into a high-maintenance one tho'.
The wording in that link above of "request" & "voluntary" by the Feds kind of answers My query, and the notation that Mopar didn't really "hit it" 'til mid-'68 would explain it as well.