I have noticed that GI WWI .45 ACP brass has a slightly smaller primer pocket, and today's LP primers will not seat without reaming the primer pocket first. I have done that, is a PITA. No idea if the brass case GI .45 ammo made in the 1920s was the same way. The WWII Evansville steel case GI .45 ammo is the same way, not worth the effort to attempt reloading it.
As recently as 10 years ago, there were full sealed cases of surplus WWII .45 ACP steel cased ammo available for sale. I do not remember how it was priced. About the same time I managed to buy around 20 boxes of the WWII steel cased GI .45 ammo for $3/box at an estate sale. It is long gone. Only problem was you had to use water to clean your pistol after shooting it to prevent rusting.
I just checked several random rounds of GI WWI .45 ACP bullets with a magnet. I found none having steel jackets. Probably cupronickel by their appearance.
Regarding the .45 ACP ammo shipped to Russia, I remember reading that when it came back, every box had mixed headstamps, like the Russians had dumped out all of the boxes, mixed them up, and re-boxed them. Allegedly Uncle Sam supplied the Russians with many H&R Reising .45 SMGs. The Russians never used them, nor any of that .45 ammo. During WWII, the Russians never lacked SMGs. They made their own by the millions, mainly the PPSh.