Yes, it is !
I remember that one, it must be from the 70's, or earlier. At the time, Graupner's HS-84 Clou, 2.4 m rudder-elevator glider was their biggest&best sailplane. A few years later came the 3m Graupner Cirrus, which at that time, was THE sailplane to have.
Also at the time, Graupner's top-of-the-line radio control was a 4-channel, non-proportional unit !
And don't even think about travel adjustment, servo reversing, etc......
The controls were either centered or fully deflected, if you wanted something in between, you had to hit the control intermittently !

My dad and I learned to fly R/C sailplanes one on of those controls.

Michael