Help identify aluminum heads

It’s more likely a “serial number”, or something along those lines(lot number, batch number, etc).
As I recall, the current version of those heads have the relevant numbers etched on the exhaust side somewhere.

I have an early set here that don’t have any “part numbers” there.

The numbers on these heads, that look like the numbers on your heads are 0902-0257 on one head and 0902-0424 on the other.