I ahve seen that in may instances the stem in a UK silver case has a different maker that the case itself. I was thinking that this came about from repairs, but there are too may, so I am specultaing that there were, at least in UK, stem-makers with their own "poincon du maitre". Is this possible ?

Yes, you are correct. There were makers who were listed as pendant makers.

thanks Jerry, but one more question : when Hamlet (act 1, scene 5, line 187-88) tells Horatio, was Shakespeare thinking of horology ? I'm afraid he did !
There do are more things, here, and this, at least to me and I guess to many other people, gives an endless pleasure.

Have a nice afternoon, here is close to night.