Hanno can clarify, but AFAIK, the only base model of Sherman to have a loader's hatch was the Firefly (in any of its variants). Towards the end of the war, of course, when the 76mm Sherman came out and ultimately evolved into the E8 model with HVSS suspension, loaders' hatches were standard.
I repeat, Hanno can clarify, he's far more conversant with the tank's ideosyncracies than I am. He'll be on here in the morning (Dutch time)...
