Note in the picture above the lanyard loop on the mainspring housing, the proper short trigger with checkering, not serrations, and the re-enforcing rings around the grip screws; all correct and proper.
Now, the original 1911A1 specs called for a narrow serrated hammer, not the Flared and checkered one on the A-O, but an awful lot of the WW2 A1s had a factory installed wide hammer. There were a lot of them laying around, they fit just fine, and the Army wasn't about to just throw them away! Finding an original WW2 A1 with a wide hammer is not uncommon, so A-Os use of this part is correct.
My vote is still with the Auto Ordinance.