Throughout my service on JP3a, 5a, Tucano, Hawk, Tornado F3, the main gun sears were only ever fitted/removed by armourers as they changed status to/from Safe for Parking & Safe for Servicing. On the flightline always Safe for Parking if available for use. Some time late 80s I think a/c parked "S" in the hangar also had to be "Safe for Servicing" before being put inside, where they hadn't been before.
The only maintenance that could be performed on an a/c "Safe for Parking" is the Flight Servicing required to either directly prepare or recover from flight. Tyre worn to limits after flight? Seats to "Safe for Servicing", change wheel assembly, seats back to "Safe for Parking". All recorded on separate job cards. On turn-round servicing, the F700 co-ordinator was able to put seat status changes on the F716 Flight Servicing Certificate & also decide from a Eng Order Book list if the repairs carried out invalidated the flight servicing or not - but it still had to be documented, as the last SNOW number would be different. That allowed aircrew to see that something had been done to the a/c since the previuos crew had signed it in & it had been officially decided that whatever had been done did not affect the validity of the preparation for the next flight. The armourers had a vehicle as they had to go backwards & forwards to the line hut so much to keep the paperwork status up to date. We were launching waves of up to 14 a/c at a time, so waiting until all had been looked at as necessary by the armourers before they did any paperwork meant the first a/c could be waiting for their signatures for some time before being made available for its next trip.