Panzerbeobachtungswagen IV had a cupola from Sturmgeschütz...
...but in this case you are looking at a turret basket lid left in open position;
You can see the new pivoting cupola hatch, introduced after mid-October 1944.
Regarding Panzerbefehlswagen IV - starting in March 1944, refurbished Pz IV were converted to this role, incl. mounting racks, transformers, junction boxes, wiring, antenna mounts, and the GG 400 aux elecrical generator. Stowed ammunition was reduced from 87 to 72 to make room for the radio equipment.
88 Panzerbefehlswagen IV were converted between March-July 1944, followed by Ausf. J version - featuring a special pivotable mount designed to fit on the left side of the turret roof through which the T.S.R.1 periscope was extended. This allowed the gunner and commander to make simultaneous observations.