Just for the record, on a GS-1, you cannot mount an uncocked lens on a cocked body, it will not let you. but if you do get it on (by moving the shutter cock pin a few mm from the uncocked position), tripping the shutter will sync the mechanism (without exposure).
However, you can mount a cocked or uncocked lens, on an uncocked body. In both cases, winding the crank will sync lens & body. Of-course having an uncocked body with no lens is a unusual state for the camera to be in, especially if it has film, you are likely have lost a frame. But the camera has been designed that you will not harm it if you happen to get it into this state.
I do not know if this is true for the ETR or SQ.
All 3 Bronica systems (ETR, SQ, GS) require shutter in lens and camera body to be in cocked position to mount/dismount lens. That is clear. Any other combination is simply incorrect, even if workarounds do exist. To give better understanding of where I came from on this (which is obvious to many, perhaps not to some):
1. Lens stored with shutter cocked simply means shutter spring is charged and remains so. If a lens is not used for a long time, it remains charged for no reason. Springs in general don't like to be in loaded condition, but does this affect its long term reliability I do not know. HOWEVER
2. Mamiya, also using Seiko shutters, and this applies to both Rb and RZ models, clearly states to unload shutters after lens is off, further provides clear instructions how to do it and the shutter locking pin is clearly in sight on the back of the mounting plate. This made look deeper into Bronica.
3. So far, form all Bronica materials I have access to, there is not a single mention about discharging lens' shutter after it's off. Not a word about shutter possibly being affected by the (totally unnecessary) cocked condition when in storage. An omission? Deliberate silence on the matter, so he chances of someone trying to mend lens to the body in wrong configuration is less? Who knows. At the same time Bronica does say that when lens shutter is not cocked, the pins need to be simply moved manually to the green dot before mounting. In other words, the possibility of such condition is acknowledged, just to me in an incomplete sentence.
4. What adds to this is where the locking pin is located in these lenses, and as it is made from exactly same material and hardly showing through, it appears to me Bronica was playing it safe and did not want users to screw with this clear (and to some, logical) option. Otherwise they would have put a marker above it, so it could be easily located.
So bottom line: Mamiya says uncock the shutter for storage and makes it clear how, Bronica stayed mum on the very same issue.
I have seen comments where one would not buy Bronica system because he did not like cocked shutter to be left such when not in use.
I wonder, if there is anyone with direct knowledge of Bronica manufacturing (no hearsay) to shed some light on why this was so. I'm happy it was easier than I thought