Typical post-WW2 configuration pistol. The military didn't care one bit about keeping parts matched up with their original frames, and mixmasters like this were the norm rather than the exception once all those WW1 and WW2-era pistols had been through the arsenals and repair depots a few times.
That's exactly right - correct as last used in service, and that is its value. Concerning Memorial Day, your pistol was probably used in WWI, re-issued for WWII, again for Korea and possibly even Viet-Nam. It deserves its own Memorial Day!
When you see an M1911 frame with a WW2-era slide and plastic grips it's usually a Korean War-era rebuild. A lot of the old M1911s were refurbished and re-issued when the military found itself short of M1911A1s, which was surprising given how many were cranked out during WW2 and how relatively limited US involvement in Korea was. The reason why we see so many commercial Colt Government Models lettering as having been shipped to National Guard units was because the US military recalled a lot of M1911A1s that had been issued to the National Guard post-war, leaving them short of pistols in return. I find it interesting that the US government didn't order any new complete M1911A1 pistols from Colt (only spare parts like slides and barrels), and simply left the states to procure commercial off-the-shelf guns for their Guard units instead.