On my Rolleiflex T the shuuter lock is different than other Rolleis. The shutter button points out to the right side of the camera and the lock is behind it and rotates up to unlock. This is very clumsey to use. The shutter release body will also pivot away from the body when the unlock is engaged if pulled. Is this designed to keep the shutter unlocked?
Otherwise this model seems like the same as other Rolleis I’ve seen and used.
I have a photo of the shutter release that I can email or text.
Your serial number falls in the early contract numbers. There may be other marking on the camera indicating if it had been used by one of the services. It's a great camera and Rollei made a lot of them. Hope this helped.