Welcome to the forum! For sure, you have what I call a First Model Utica, most likely made before WWII. The First Model Uticas had a steel trigger guard like yours. Later 2nd Model Uticas had an alloy trigger guard. The date codes did not start until 1947. The code was a letter inside a circle with a number. The number was to identify the inspector and the letter identified the year. A = 1947
As to the choke. I have all catalogs from 1937 to end of production. They do not mention any particular, but imply all chokes are full. I have had a very few people tell me their 220's measured modified or something less than full. Most likely these were opened up after leaving the factory, but no proof of this. These guns had assembly numbers stamped in front of the barrel lug, on the inside top left of the frame, and on the wood under the butt plate. These were a variety of letters and numbers, and I suspect that if this assembly number contained an "F", it was mistaken as a "full" choke barrel.
The forearms were not attached with a screw like your gun, unless this screw was just added for strength. Yes, with a normal 220 without your screw, you should be able to pull the forearm off easily by holding the barrel with one hand and placing your other hand on the front of the forearm and pulling away from the barrel. Please send a picture of the inside and outside of your forearm and I will try to give you some better information. Once I get your picture, if it is not the correct forearm, I can send you a picture of what the forearm on your gun should be. I hope this helps some. Best wishes, Garnett
