Hi Pawel,
I had a long moment studying your article and model this morning and I'm still discovering new bits to add to the Tamiya kit
I had a look at Rob MotorPool gallery and found this picture
This is a part of mystery unveiled, I still don't know if you're right assuming it could support the workplatform. Anyway, it must be added along with the other one near the exhaust. This one, I did see it with the new exhaust type for the moment.
A question about your model : did you modify the bustle rack shape ? I'm in the process of building the turret myself and wondered if it were easy or not. My plan is to add a bit of plastic to the floor and re-do the vertical wall with thin plastic card.
olivier