AD Pickup,
I was trying to point out that replacement engines from Chevrolet came with a blank distributor pad where the serial number should appear. Depending upon the titling and registration laws of the state, either the the serial number of the original engine (which was then scrapped) or a new number assigned by the state was to be stamped into the distributor pad. I have heard of other practices, legal and otherwise.
In any event, the serial number on the engine in your friend's garage may not be much help in identifying the which engine it is. Getting fifty years of crud off to find the casting number will be a messy job.
Hoyt
