Just a clue and a translation of the description of those photos of the remotely controlled M-41:
First photo
"Test vehicle, self-constructed by the armed forces, this former light tank M-41, with the turret for its 76,2 mm
gun removed. This modification is an attempt to control the vehicle by radio (note the rod aerial) to use it for
different tasks, e.g. detecting and clearing mines. Unfortunately, more specific information cannot be given."
The wording of the last sentence, to my opinion, makes clear, that those tests were classified.
Second photo
"The remotely controlled vehicle from the rear. The cladded engine cover and the mounting for the antenna are
clearly visible. The tests were conducted by the WTD 81 in Greding [Wehrtechnische Dienststelle = department for
defence technology] )
No mention of counterweights, no "big" engine compartment (it just seems to have got an additional cover), and principally,
not even the purpose of mineclearing is confirmed, it's just mentioned as a role for remotely controlled vehicles in general.
And of cousre, as dan-inbox said, no relation to casemate tanks!