: Isnt one of the sub reg hands incorrect, thought ine should be the
: chunky square style one?

The Cal 12 Monza line should have two matching chrono needles, the Cal 15s have one white and one red. We normally see Monzas with the chrono needles with the rectangular ends, but looking at the '78 catalogue it does show round-ended ones:

Could be the right chrono hands then. But my first reaction when I saw your post was to agree, I'd expect to see the rectangular ended ones.