Magnus,
You are correct that the early launch versions of "simple" watches at L.U.C viz. L.U.C 1.96, 1.98 and 3.97 had closed dials.
That is why I wrote: "precedence of openwork dials for the inaugural editions of their new complicated movements"
If there is something to see and the openwork does not affect function, openwork dials may be possible....
Regards,
MTF