Good info here, Bob!
Here's a few rounds from my collection:
The WW I era rounds have the stab punch marks, three around the case neck. This was to hold the bullet during recoil when used in the M1917 Revolvers. The position of the unfired cartridges in the revolver caused the bullets to "walk" forward under recoil. The ACP case couldn't be crimped, so the "stab" crimp was utilized. Taper crimping eliminated this problem, so only WW I era has these points.
Copper appeared to possibly be in short supply early in WW II. Chrysler Corporation engineers explored the use of steel cases, using coatings to prevent rust, stainless steels not being so developed at the time. These steel case .45 were made in the Evansville, Indiana, Ordance Plant in 1942-1943. Production was so efficient that the Sunbeam Plant was employed to make additional cases to be loaded at the plant. The "E C" headstamp is for "Evansville Chrysler" and "E C S" for "Evansville Chrysler Sunbeam". The situation eased after 1943 and brass cases were utilized.
Here's some of mine.
Not nearly as old as yours, tho. I used to have a 20 round box of .45 ACP ball dated 1918. Lost it in a household move somewhere along the line.
You collectors will probably cringe when I write this, but 20+ years ago I came across some old .45 ACP tracer still in the original skinny box/wrapper (I think I got it at a garage sale in southern Mississippi). Being a shooter, I promptly headed to the range, opened and fired it. Only about half of the 20 rounds ignited, but holy smokes, the ones that did were like tiny meteors zipping downrange! Brightest tracers I've even seen or fired in any caliber!