Must first admit to not reading every post.
That said, as an old Navy vet, I have personally watched the progress made over the last 30 years in ship design that uses modular construction and quick swapping of system modules for tailoring the load out for the mission.
When I was in the Navy, things that are now being done in a day, would have required an extended refit in dry dock.
Old missile systems used to store segments that were assembled below decks ans then transported to a launch rail before being fired, limiting how many could be fired to no more than 2 per minute. Today's modern vertical launch systems are such an obviously superior improvement that it makes one wonder why it wasn't done that way from the beginning.
Looking at the weapons mounts on ED's ships, it would appear that the platform bases are externally uniform to accommodate fast swapping with common control elements below the base. The graphics mechanic displayed is a bit illogical as it would seem more likely that the swapping would take place externally, but dropping a rigging from overhead to swap a new weapon to the platform base should be fairly simple and quick. Bottom mounted stuff isn't any more of a problem using a lift instead of an overhead winch.
If such systems were automated with quick release mountings, it's easily conceivable that swapping external mounts could be done in a matter of minutes.
Internals would present more of a challenge, but clever design that would expect frequent module swapping could achieve similar results when you look at the progress that has been made, just in the last few decades. A steam driven ship required lengthy repairs if there was a problem with main propulsion. Then the Spruance Class destroyers started using Gas Turbine jet engines that could be swapped out in a matter of hours dockside.
1300 years is a long time for creative ingenuity to make improvements.