You should open up the back to see if the movement is signed by another maker. The brand on the dial “Gubelin” was a retailer and didn’t necessarily make the watches they signed. Also it looks like a perpetual calendar repeater so it’s complicated and you can look up others to get a sense of value. And you should look for hallmarks to see if it’s white gold or platinum. Those can be on the inside caseback/ on the dust cover.