Think they did, Bit suprised to be honoust as Dutch Mil recently asked aircraft to change their c/s if it was Different that his atc callsign. Maybe depence on controller on duty.The ATC c/s of the RC-12 was Argus15 and of the C-12 it was Duke07.
Don't know if they had different c/s on SBS.
Thanks though, we still have to be sharp with SBS-1/atc callsigns for the time being!
Grtz
Joost