That is a nice looking gun. The 1911 was succeeded by the 1911A1, which had a variety of minor changes: shorter trigger, curved backstrap below the grip safety, longer grip safety tang, shorter hammer spur, shallow finger relief cuts on the frame behind the trigger, slightly different sights, etc. That was the main production version in World War II. The original-type 1911's were used as well, of course, but many had old-style parts replaced with new-style ones over time. An all-original 1911, as this one looks to be (I am NOT an expert on them) is a nice find.
The little horse on the rear of the slide is Colt's trademark. Colt made most of the 1911's in World War I, although I think Remington-UMC also made some. There was a much wider variety of makers in WWII.
The magazine are two-tone because of Colt's manufacturing process, which included hardening the top by dipping it in a hot cyanide bath. Many WWI issue mags had U-shaped loops on the bottom of the magazine for a lanyard. I don't know when that feature was dropped - possibly well before 1918. I think a lot of WWII magazine were made by companies other than Colt (General Shaver?) and are not two-tone. Colt changed its process and stopped making this kind of magazine sometime after WWII, I think.
The ammunition appears to be from WWII (1944). It should be non-corrosive and safe to shoot, but it may have collector value in itself. Ammo is expensive to ship, though - the US Mail won't take it.
BTW, thanks for putting up good pictures!