True, anybody messing with USGI rifles ought to know the difference between a 1903 with "ladder" sight and a 1903A3 with receiver sight. I don't know if theoretical considerations of sight radius entered into the change. More like the newer autos, M1 rifle and carbine, had receiver sights and the secondary standard bolt action ought to aim the same way. But that is just speculation on my part.
The 1903 afficianado ought to know that Remington made the 1903 for a while before the A3 was designed. There was even a 1903 Modified still with ladder sight but some cost cutting measures made before the A3.