You do need to be careful with these as has been mentioned. All are derived from the 330 and these are the derivatives:
View attachment 597562
Both 342 and 344, use a rotor 3421017 and are the only calibres with that rotor that I see immediately. The 343 uses 3431017 although the difference is probably just going to be the writing on there. It's not easy so, get your watchmaker to buy the parts.
The 3301403 that
@X350 XJR linked to above is not correct for a 342 but it is for a 330/340/341/350 as examples. Most of the others, including 342, use 3321403 and you can tell because the screws go in from the visible side with the later design. They all use the same rotor axle though and your watchmaker should be able to source these if your rotor needs a replacement.
Good luck, Chris
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