Its Tri-Service, it just happens that this particular one was issued to the Navy, hence the "ShipCat". label
The markings are a bit strange though, nearly ALL markings I've seen have the stencils properly horizontal, the NSN (NATO Stock Number) is angled slightly, which is strange, plus its duplicated. On the larger NSN there is a /2 at the end which has me baffled too, its painted on separately to the NSN so may not be connected to it at all. Also, the markings on the lid are unusual, it is usual to place all markings on the main body of the box, probably in case they get detached and are replaced on different bodies (easy to do with an H82). Looking at it again, if the larger NSN was stencilled horizontally, it would cover the qty amount, 125. Perhaps the stenciler was just making it fit on the box.
My guess is that it is a Fraction box made up in a depot. I can't be sure as I don't have any references to how ammunition was packed in the 80s, but nowadays these are packed in H83's.
The ADAC (Ammunition Descriptive Asset Code) number is missing, (which is used for accounting separately from the NSN) but I don't know when ADACs were introduced.
The numbers on the lid don't mean anything to me at all.
Can you show the label on the bottom right, might get more info from it.