It's authentic. All of the pieces are signed, too. MrG checked them anyway with his testers. Sterling. The watch guard is signed with this lady's name and is very similar with the seed design...but in turqoise and what looks like mother of pearl or oyster:
Zuni Native American Turquoise Watch Tips by Caroline Malani SKU#226715
Zuni Native American Turquoise Watch Tips by Caroline Malani SKU#226715