well I believe that the ammo itself is still vaccum-sealed.
That is certainly rust on the weapon and I believe that's rust on the clips as well.
I'm really happy that most of my military service was spent around land forces where shipboard saltwater corrosion wasn't much of an issue. Even multi-week long monsoon showers didn't usually result in ruinous rusting, just a washing away of any petroleum-based lubricants or coatings used to keep the guns going. Neither is shipboard maintenance helped by the quaint naval customof mounting the gun on one end of the vessel, then storing the lubricants and cleaning solvents for it in a *paint locker* at the other end of the tub.
But I've seen M2 heavy barrel .50s in much worse condition after a couple of months of exterior mounting on the outside Chrysler gun mount atop an M48A5 tank, instead of inside the commander's cupola where the ammunition supply was limited by the cramped internal space.
I'd bet on that .50 working just fine, and after firing the crappy links can just be pitched over the side. They're lucky their security doesn't depend on an M60 MG or an M134 minigun in that condition.
Ever wonder how an aircraft .50 looks and works after 30+ years under water?