1969 engine VIN discussion

Cast in 6/25/68 (or 8/25/68) and machined and built in 12/27/68. That's almost the middle of the production year. They started stamping blocks in mid year of 68 and all 69's had full vin stamp right? Or is that all hearsay?
You are right. Federal mandate required all engines and transmissions going into 1969 year model cars to be stamped with the complete vin. Mistakes happen and I have seen some with no vin whatsoever. But they are all supposed to have complete vin stamped