the dimples on the water pump flange
I think it is an early head as the center waterjacket hole is not punched out. I believe that started in 1929.
Not quite right, the early heads had a center hole, it was just smaller.
Tbh, I wouldn't recommend using this head for anything since the center cooling hole seems to be missing entirely, which will compromise the ability to cool the head.
The blocks had a hole there but the heads didn't?