Hi José
Based on my references, the bolted segment between the hatches where found on hexagonal T-34s produced at the UZTM factory. However, it wasn't found on tanks (at least most of them) produced at other factories such as No. 183 or No. 112. I can only assume that this panel was a standard element of the design, but was omitted by some factories to simplify production. As I understand it, that detachable panel’s purpose was to allow the removal of the fuel tanks without removing the entire turret.
I would say that if you want your model to represent one produced at UZTM, include the panel. If you want it to represent another factory, you can leave it off.
Good luck