It does not help that were are usually 4+ groups involved at the time, from ebauche stages, to casing, to final retail. The fact that it is not known to date tells me it is likely a complex story.
Thanks for the setting works pic. Amazing to see no marks at all. The austere & fragile-looking setting bridge--and lack of any patent stamp--make me think of Russbach-Hänni ebauches, finished with their setting works. Here's a known RH, with their setting works. Yours seem like a similar treatment.
Bridge matches are out there for your middle bridge. None for overall build yet. Here's one ad example from 1913. Yours is much better quality. I maintain M&V is a contenter, also Russbach-Hänni themselves.
I do think I've found where your watch may have finally ended up, why it is not marked "Concord". See top right in this 1918 ad, which I think shows a variant of your watch.