Original Delco regulators of that time period would have had information stamped into the base of the regulator....7 digit number, date code etc. Aftermarket regulators typically have ink stamping somewhere on the side of the base plate or underneath. The modern day aftermarket regulators that are made in India have ink stampings on the cover of the regulator. Modern aftermarket regulators that are made in USA will have Made in USA physically stamped into the base but may have ink stamp information on the base plate or underneath. If you do find a number of any kind let me know and I will see if I can give you the info on it.
Ken
