Nothing wrong there. Usually called 'flipped' hubs, done so singles track better with the fronts.
Unscrew the retainer nuts, after prying up the keeper flange.
They shouldn't be too tight.
Keep a clean towel of pan under when pulling the hub off, as the outer bearing will make a break for the mud/sand.
The inner bearing is held in place by a seal, that being held in place by a large snapring.
You'll have to pound out the seal and bearing with a brass rod.
Clean everything up and inspect.
In many years of flogging tactical's, I've never seen a wheel bearing worn out. Rusted to bits, yes.
Reason being, the Military changes bearings way more often then needed. Preventative Maintenance. An Old Motor Daddy once told me its cheaper to change before they go bad, then to repair when they go bad. Yeah, the only time I ever saw bad bearings was when someone put the bearings back in, and over tightened them. Not long later, you could cook on the hubs!
Good long-fiber grease is the best thing to use, stay away from disc brake (black) grease.
DG