Limit Swiss Made Open face Pocket Watch

[Noggin]

I have been left an Open Face Limit Swiss Made pocket watch
Which I believe is encased in a bronze Dennis's 'MOON' watch case (i believe it to be bronze as I cannot see any hallmarks) The case does have a serial number which appears to be untraceable (709181) and on one of the bezels (1819)
The mechanism is however a Rolex Lever Swiss Made mechanism
This mechanism has no serial number nor any other visible markings as in number of jewels.
I am desperately trying to find out a little bit of history about the watch and value for insurance purposes
The watch is in perfect working order and I believe it to have been made between 1903 - 1920
Can anyone help with my research
Thanks Noggin