Well, I know one thing for certain: the 40mm you put on it now is not the correct one. The one you took from the parts sheet, is pictured below:
The one underneath it on the parts sheet might be closer, although I think I have never seen this particular mounting before, so you might have to draw it from scratch.......
as for the exocet launchers, they look nice, but I would suggest playing around with them a bit. I am not certain if I drew these myself back then or copied them from someone, but this drawing has some exocet launcher which are in my opinion slightly better still.