Looks like a bushing to me. Doesn't matter, it's still not a road trailer because it's unsprung. When I was towing howitzers which are also unsprung we used to blow up tires with regularity at high speeds. You wach the tire go up in the air in the mirror and wince because there is no suspension to absorb the blow. Pick up your trailer even 6" and drop it and there's going to be a good impact on the tires and the frame and on whatever you are hauling. When it goes up it will leave one tire on the ground and the other floats in the air. When it comes back down it's going to slam down when the tire lands. That's why that bushing is shot. It's meant to be slow speed. It got hammered when they decided it was a road trailer. It's going to kill lights and decking and everything else unless you are just using it around town. They are great offroad though. My friend has a quad trailer like that and it goes over logs through the woods easily.
If the bearings are standard size you should be able to get a pair of
torsion axles for $500. I also see that thing has hydraulic brakes--at least it would if you put lines in it. So if those are any good still you need a
coupler/actuator--which is a coupler with a master cylinder built into it.