Much of that is correct Steve, however....
My Sherman is a typical early M4A4 and has the Westinghouse traverse and no applique patch over the thinned section. This was normal in M4A4, the electric traverse being the standard in this model.
So, non applique, thin turret electric traverse were common enough in action.
There are two stages in terms of applique. The original, field fitted kit which mine has. This is simply three, 1" thick plate over the ammo racks and none on the turret or in front of the drivers hatches. There may have been a later field kit that included the front plates as well.
The welds on these plates are multirun with none on the lower edge and have all been done with the vehicle in the normal position.
The later, factory fitted plates were thicker, 1 1/2" and were fully welded with the hulls on their sides. These vehicles also had plates in front of the drivers hatches and would have had the turret patch if not the later, thicker turret.
Many early M4A4s were retained for training in the US before being rebuilt with full applique and being sent to the British Army.