RoF is a subjective thing, but I would be inclined to give the benefit of the doubt and give a RoF of
[1].
The vehicle had a lower RoF than might be expected for the size of the gun due to the loader also being the tank commander.
While with some T-34 (76mm) crews the commander could double job as anyone, one account had the commander as driver, the commander usually doubled as gunner, not loader. This is in contrast to British practice for their few 2MT (Light Tank Mk VI, Valentine II, Crusader III) where the commander did indeed double as loader. The British thinking was that peering through a gunsight, tracking a target, was too concentration and time intensive for a double job crewman. In ASL a Soviet 2MT (except the T-80) is a RST (ditto Italian), while British 2MT are ST.
The T-34 m40/m41 have RST and
[0] RoF, while the T-34 m43 with the
exact same crew assignments has RST and
[1] due to a bit more elbow space in the turret. While the 57mm rounds were roughly as long, they were lighter, so I would be inclined to up the RoF to
[1]. This would also follow the existing pattern of giving guns ≤ 57mm a RoF of
[2] for T and
[1] for ST/RST.