[SS427]

I recently looked at a '67 Chev wagon with a 400/427 tri-power that was being touted as a GM exec car. The engine was correctly coded but over the VIN stamping was a "W" over a "V" and then (if I recall) a 5 digit number. I assumed this to be an engine rebuilders code and job number. Has anyone else seen the W over the V stamping on an engine pad? TIA
Rick