The GMC 270 in the 54/55 GMC COE that we are "restoring" is a factory replacement engine. All that is pressed into the pad is "270". I do not know what (if anything) the Chevrolet factory replacement engines had pressed into the pad on the block.
The 235 that came in one of my 54 Chevrolet pickups had a donor replacement 1954 engine that has the engine serial number crudely ground off of the pad.
