Well done, great detail and a nice looking bike. I'm currently rebuilding a 1984 Fullpro-S (in Germany) for similar reasons - wanted a vintage Shimano build, and what better way than to go with a Japanese-ish frame. As you will know the catalogs are very detailed regarding frames and groups - the 1984 Fullpro has a mix of AX and EX components including an AX stem and seatpost. I'm not a fan of the AX brakes so I'm happy that mine has the EX calipers and slotted levers with external cables. My delve into detail has also led me to the CAD system and 3D printer, in my case for the blue dustcaps that the earlier AX pedals have. I'm not sure which model numbers had the blue caps vs the exposed hex socket (like yours), but the Koga brochure for 1984 shows the blue caps and my pedals still have one so at least I had something to measure up for the model. Pic is an internet example, same as (but not) my pedals.
