Tactical missile systems can be seen as incremental improvements on existing systems. Nukes would have been a violation.
I agree that the terms of the armistice are and have been largely a dead letter for dacades, and that's why I couched my comment in the vernaccular, as in "Oh, and Dude, you know, keeping a, er, amphibious rodent as a pet, within the city, well, that ain't exactly legal either."