Think about the reason behind why the terms are used. It's not about dates of the war, it's about production processes. Before the war, Colt concentrated on fit and finish. Polishing and finishing took hours or days. Many pistols had to be painstakingly hand timed by assembling, checking, and disassembling to adjust parts.
WWII ended all that, there was no time to waste. Polishing became much more basic, finishes were changed to low gloss, and much hand fitting was eliminated. So wartime production is usually considered "rougher." After WWII Colt slowly began to retool for commercial production. But by then, people had retired, early equipment had been moved to make room for military production, etc. Many pistol lines were determined to not be profitable and were phased out of production, or never restarted. Finishing processes were a new amalgamation of the early ones, WWII ones, and newly engineered ones.
So, there are Pre-war, Wartime production, and post war colts. The war period also had phases, the early war pistols are nicer than the later. Same thing happened to all weapons manufacturers, be it Colt, Smith, Walther, Mauser, Radom, etc. The pre-war and early war production are nicer, but by war's end, most pistols were being cranked out with very rough surfaces. The US, winning the war, didn't go that far down in quality. Since there is no way to tell what month the quality changed at Colt, everyone considers "wartime production" to be starting early 1942.
The single largest difference in pre war and post war Colts is the finish. Colt did not get back into production until 1946, and at that time the finish was changed from the oven blue to hot salt blue. At that time they had firearms in various stages of completion, and this formed the basis for some of their post war production. Some of the guns were already blued such as the pre/post war Super .38's. The serial number is pre war also, but they were probably not assembled to be sold until 1946.
If you assign dates to what they will be called where do the 1911A1 military Colts fit in? They were made pre WWII, during WWII, and possibly a few after the Sept 2, 1945 date, as the last shipment left Colt on September 18, 1945. With collectors the major difference in the 1911A1 was the change in finish from blue to phosphate. With the left over production from the 1911A1 Colt began manufacturing the Government Model in 1946.
I see the real difference as being what was post WWII production. At the time period we are discussing Colt was never concerned about manufacturing and shipping guns in strictly numerical order. If you prefer to use the "war time" production it would require a factory letter to distinguish between post war and a war time production on some guns. The early war time production of commercial guns was simply a brief carry over from pre war production.
I agree with Oyeboyen as well, but I also believe that the pre war/post war distinction is often used to distinguish handguns that were manufactured to pre or post war specifications as far as design changes and finish. For example, the change in the crane retention for revolvers is "post war" even though some "post war" revolvers still had the earlier retention mechanism.
The "Post-war" guns were the same design guns as the "Pre-war" up until the transition period in the late 1940's.
It was during that period that the pre-war features like the hammer shape, cylinder retention, and front sight began changing.
So my opinion is that "Pre-war" TYPE guns were made up until the late 40's and were the exact same design guns as those actually made before the war.
In this case, you can be talking about the fit and finish of Pre-war versus Post-war or the actual design differences in which for a period of time there was no difference between Pre-war and guns made after the war.
This one was shipped in September of 1940. It is different in that it was fitted with the Swartz Safety which was first used in late 1937, and it's used ended when production of the Government Model was halted in 1942. When production of the GM was resumed in 1946 the Swartz Safety was not used.