Marc:
The diagrams are a good find. I would be interested to figure out what sources they use, but if we assume (the not-yet-proven case) that the diagram is reasonably accurate, then I believe the diagram supports my original statement.
Visual recognition cues:
Examining both the picture I provided and the diagram in the link, and focusing on the right side of the turret for now (right side from the crew perspective, left side if facing the tank), I observe that the curvature towards the back panel (the rounding of the corner) starts at about the line across the front of the turret hatch. Clearly the turret side is already rounding towards the back by the time we get as far back as the right side periscope.
I know I promised I wasn't counting rivets, but if you look at the turret side rivets in the diagram you can observe that the turret-side rivets at the bottom (near the hull) are more widely spaced than the turret-side rivets at the top (near the roof) around the periscope, which is not true forward of the periscope.
(There may differing numbers and patterns of rivets in the photo, but who's counting? Not me!)
On the model shown in the OP, the turret side is clearly still a flat surface at the line of the front of the hatch, and the curvature clearly does not begin in front of, but rather behind, the periscope. (I can't see any rivets, but then I wasn't going to count them anyways, I promise!).
This is all detailed stuff, and matters little even to me. What I observe as important is not these details, but the overall impression of how the turret looks. To me it looks too triangular, with the turret rear not rounded enough.
Just my opinion. I would be hesitant to suggest it was even my $0.02 USD worth, but then I offered it at a discount.
-Mark
(aka: Mk 1)