It did not occur to me for some reason to do this at some point during the build, I guess I assumed they came pre-greased. So at just under 50 hrs on my craft, I heard awful noises as I pushed her in the hanger yesterday! I hooked up the grease gun, and it must not have been pre-greased at all, it took a bit of pumping to fill it. Probably will replace it with a sealed bearing wheel now anyway, but just a heads up for others who may miss this like me.