When traveling from outside the US, there is an exemption under which there is no duty; I think the threshold is $800. I don't know if that's how it works on shipped items or not, but I've bought several watches from C. Ward that were less than that, and was never charged duty. That said, it could happen, but on a ~ $330 watch, it won't be much.
Read this information from U.S. Customs and Border Protection regarding rules for importing. Most of the information posted on forums is 'opinion' and not fact. By the way, the country you're importing from is irrelevant unless it's coming from Canada or Mexico and was manufactured there, in which case it will be duty free (or have a reduced rate) due to NAFTA.
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