Carter 2bbl ID...?

Are there significant differences between a carter 4113, 4114, 4115, and 4116?
Is this number on a TAG (long gone) or stamped someplace?
I have a 1933 cast into the body under the Carter name on the fuel bowl, and a 6-1902 cast into the air horn.

I'm curious why Napaonline bothers to ask you the carb type when they list 2bbl AND 4bbl carbs after you input all the data they ask for.

Is there another number stamped on this thing?
The online listing shows these four carbs all take the same rebuild kit.

Any info or feedback is appreciated.