Sir as I am aware of the sighting system never changed when the round changed. It would have been 150 gr spitzer at 2700 fps originally. The M1 30/06 didn't come around until 1926 and was as you know a 174 gr boat tail at 2640 fps. 1938 saw the M2 in a 152 gr. gilded metal jacket at 2805 fps.
Most of the 1919 rifles set in storage until WWII so truthfully it most likely never saw a 150 or 174 through it if it was ever issued. The difference between the 150 and 152 are so minuscule, I didn't want to search for a 152 bullet so I just use match 150's for target and boat tail spitzers for hunting. I like 48 grains of 748 as it shoots well in the springfield and garand for me. Hogdon lists it as 2810 fps in a 24" and 46,000 cup.
I do not believe the sights were changed until 1942 with the M1903A3.
Any of the 3 cartridges should work out fine. I use a 150 at about 2800-2820 fps, works out well on my scoped A4.
Blessings
