Carb models are a moot point nowadays. Why? Because all the part kits are generic and contain the same parts, mostly Main Needle Jet screw are which was changed after the TSX-33 unit. Since you did ask, here goes. The MARVEL-SCHEBLER carburetor, model № TSX-33, FORD p/n 9N-9510 was used from 1939 thru early 1948 on the N-Series tractors. The only exception was the TSX-38 carb, FORD p/n 2N-9510, which was identical to the TSX-33 only it had a double-throw choke lever and was used on the Industrial Model and the 2N Warhorse Model. Then in ’48 it was revamped to the TSX-241 model, FORD p/n 8N-9510. There were three EC changes to the 241, designated as A, B, and C but only minor internal ones involving the economizer jet, but the biggest change was the main Jet Needle. Identifying the TSX-33 and 38 can be made as they were originally with the Marvel-Schebler name as cast raised characters on the lower bowl half and used a Main Jet Adjustment Needle that had a splined knob and a locking plate screwed on the lower half. The “TSX-33” (or 38) model number was cast recessed on a boss I call the ‘paddle boss’ as it resembles a ping-pong paddle. When the new TSX-241 unit was released, the MARVEL-SCHEBLER name was eliminated from the lower bowl half but now cast recessed on the upper half along the edge of the milled intake mounting surface. The paddle boss now had a brass ID tag riveted on. This tag had the Model Number and a date code stamp to designate when the unit was first manufactured at M/S. I have seen some TSX-33 units with a brass tag as well and I suspect these were made at the time the brass tags were released to fill new orders for TSX-33 units. The big TSX-241 carb change was the revamped Main Jet Needle. It no longer required a locking plate and was now a spring loaded device to maintain position. Today, any of the TSX models will work just fine on an N. The parts suppliers no longer make the Splined Main Jet Needle Screw and ALL kits are generic with the newer Main Jet and spring. If you have an OEM TSX-33 carb, you remove the old Main Jet and locking plate and use the new spring loaded Main Jet Screw supplied in the kit. Note the Main Jet idle screws.
Look on the teardrop shaped bump opposite the choke lever. Should be something stamped there. TSX33 or TSX38 or TSX241 etc if it is a MS carb. If it is something else I don;t know.