The core on the 29-30 year is 18 1/8 X 23 13/16 and the
31-32 year is 17 15/16 X 24 1/4.
These numbers were from the Filling Station catalog.
Would they interchange? I don't know. I'm on my third radiator so I'm going to go out and measure all of them in the morning. My first is a modern style without honeycombs, the second is a honeycomb that blew out at the tank, the third is a honeycomb that overheated last time I drove my 1929 Sedan.
I don't know if all of mine were "the right size" so maybe I can see what will fit. I like that aluminum one you have pointed out.
Jim