1967 GMC V6 Stamp Number

[HBHarleyman]

I recently bought a 1967 GMC with the 305E engine. The stamp by the pass head says 305E 448472.

I'm sure it's original, as the protecto-plate has the 305E and the same number 448472 after.

Can't seem to find online what that 448472 means? Looked on the 60-66 gmc website as well. Seems as if people think it means nothing. Maybe it's just an engine sequence number? Does not seem to be any kind of date code like chevy's.

Appreciate any expertise! Really Bugs me