right angle casting

[NewKid]

I have been looking at the mortec sight and it shows that a right angle casting identifier was used on 1968 #040 heads. The heads that I have for the same year has a right angle casting identifier but are the #3911032 heads and are suppose to have the small valves with the 70cc chamber volume. On both heads there is a stamped letter of G on the face of the passenger side and then the same stamp on the backside of the drivers side. Someone will probably want me to take the heads off to make sure what this means but i am trying to keep the motor together because of the lack of storage. Does anyone know what this right angle casting identifier might mean? Thanks