Old Pocket Watch "Medailles di Or"
I’m thinking the watch maker won six gold medals at some kind of expo. There was one in milan in 1906 that featured a lot of watch makers. So that manufacturer won six medals and put it on his cases. People do the same thing today - just think car advertisements that run through a bunch of awards.
As to the metal content of that specific watch case - it should be marked. If not, then take it and have it tested. The majority I come across are gold filled but solid gold ones are not uncommon.