Veeeeery interesting
First you need to determine the venturi diameter and thus the carb venturi number. Obviously if it works out to be a smaller throat then that changes the carb part number and engine(s) it may have been fitted to and hence the aircraft
Fortunately it is very easy to determine if this is a "#12" carb by just measuring the venturi diameter.
Based on your data it looks like an NA-D12 to me - its almost certainly an updraft model and the float chamber is definitely behind the barrels so you are looking at probably a very early R-1820 engine or similar - DC2 maybe You will note from the reference below that NA-Dn type carbs became obsolete circa 1930 so that potentially rules out the DC2 and makes life even more interesting.
Stromberg used a simple identification scheme where a series of letters and numbers were assembled to identify and describe how a carburetor was constructed. The first two letters described the carburetor design, followed by a number that identified the size, and numbers and letters to identify specific design details and modifications.
The first (two) letter(s) comprise a Basic Design Code that places the Bendix Stromberg carburetor in a design category, where:
"A" – Pressure Injection Carburetors
"E" – Pressure Injection Carburetors
"NA" – Float-Type Carburetors
"P" – Pressure Injection Carburetors
Example: NA-R9G
Prefix- "NA" – for float-type carburetors followed by a "-"(dash)
The next letter indicates type, where
"S" – Single venturi updraft designed for two, three and four cylinder engines in the 25~95 hp class. NOT fitted with economizer, acceleration pump or mixture controls.
"R" – Single venturi updraft, designed for engines of all types in the 50-400 hp class. All are similar in design and incorporate needle valve type mixture control, accelerator pump and economizer. Some bodies are interchangeable in this series and deferent design economizers are used.
"D" – Double updraft venturi, with the float chamber to the rear, was considered obsolete c.1930
"U" – Double updraft venturi, with the float chamber between barrels.
"Y" – Double vertical venturi (updraft), with two float chambers fore/aft of barrels.
"L" – Inverted, down draft venturi.
"T" – Triple venturi, double float chamber fore/aft of barrels. The NA-T4 series is the only known model. Designed for use on Wright J-5 and
other 9-cylinder radials, where each venturi feeds three cylinders. It has float similar to Y series, but with back suction mixture control. No
economizer or accelerator pump.
"F" – Four-venturi with two separate float chambers.
The number following the type is the venturi diameter and 12 indicates a 3-1/8 venturi (2 indicates 1-1/8)
Subsequent letters are variations
My references only cover NA-?12s for Pratt engines and Pratt went to the PD series carbs in the mid 30s for new designs,
The Allisons used PD-12 carbs from the -7 on and all Allisons had flat not angled intakes
Here is the list I have of NA-?12 carb installations from a NASM document. Unfortunately it only shows Pratt and Packard installations
My other bible (USAAF Maintenance Interchangeability X ref charts TO 00-25-29 (1943-12)) does not show any NA-?12 carbs left in service at that stage, only the smaller carbs for Harvard and smaller aircraft