USPS only insures up to 5k i think? I hope that will cover the cost. With all the info you have, i'm sure it will not be a problem.
I had to claim insurance on a breitling watch years ago, I remember I spoke directly with the kind manager at that particular post office in person, she walked me through everything, in the end, she made sure I collected the money.
I know everything will work out, if no watch, then for sure you will get some money...
If you ship alot of watches, i guess it's only a matter of time before something like this happens. It could always be worse.