This particular phone in Titanium Silver is covered by US Manufacturer Warranty. I did a huge investigation about this issue contacting directly Samsung and verifying everything with Best Buy Customer Service Representatives.
As of now, there are only 3 unlocked Galaxy models that are covered by Samsung Warranty in US:
1. Samsung Galaxy S6 - Black
2. Samsung Galaxy S7 - Black
3. Samsung Galaxy S7 Edge - Titanium Silver
You can verify this info at samsung.com official site