ORIGINAL: KG Erwin
Maybe not so much the Marine squads as the engineers, light mortars and MGs. The sea-change was in the replacement of the Springfields with the Garands. That's why I differentiate between the .30 cal MMG and the 43 .30 cal MMG -- it's the secondary arms.
As for the Marine squads, the important thing is to keep in mind the differences between the D, E and F-series units, which roughly correspond to the years 1942-1944.
OK, so I'm pedantic about this (sorry), but they were called Rifle Squads -- technically speaking, there's no such thing as a Marine Squad. I'll just change 'em back for my personal OOB. [;)]
I made them "Marine" squads so that when they fight alongside the US Army units, they "stand out"....otherwise you'll have Rifle Squad and Rifle Squad, so which is which? [:D]
Don't you want your Gyrenes to be easily recognized amongst all those dogfaces? [;)]