No, I mean WWI. The Marines had 03’s and most of the Army was armed with 1917 Enfields.
Do we know if the Marines specified only 1903s for its forces, or was it more a matter of the size of the Corps versus the expanded Army? Like the much-smaller Corps could be supplied from 1903s on hand, while the Army would need vast numbers of new rifles anyway so give ‘em the 1917s?