I had originally ordered these heads cut to 62cc but i strongly doubt it was ever done as they were measured at the shop and came up 67cc.
Haven’t those heads been ported at least a couple of times since you originally bought them?
Probably got some chamber mods along the way, and a valve job or two.
If the chamber volumes weren’t checked after each of those processes...... who knows how and when they went from 62 to 67...... or if they were ever 62 to begin with.
I just freshened a set of aftermarket Pontiac heads that had cnc ported chambers.
Over 3cc difference between the two heads.
The only way to know what you have is to check it.
