You are looking for a "stamped" (recessed, not raised) number, ending with the letter S as in (S)am.

http://www.thecarburetorshop.com/Carburetor_ID.htm#IDCarter

All casting (raised) numbers are meaningless.

Some of the aftermarket carbs were identified by tag only. Once the tag has been removed, the ONLY method of identification is to measure and compare all machined castings against the original blueprints. Cost to do so will exceed the value of any model YF.

Jon.

Good carburetion is fuelish hot air
The most expensive carburetor is the wrong one you attempt to modify.
If you truly believe "one size fits all," try walking a mile in your spouse's shoes!
The Carburetor Shop