buddridge,
Here are a couple of photos of the '30-'31 upper tank, original tanks have the three vertical drawn pressings fore and aft.
One of these tanks has the early style baffle, the one with the large dent, the other is the improved baffle design.
The face of the core should have dimpled fins between the tubes and the ******** the bottom tank should be riveted in place and soldered.
Hope this helps.
Darryl in Fairbanks