Well, I think I came up with a solution that will work for my missing dustcaps (the metal things that cover the hole in the middle of the wheel). My local autoparts place didn't carry a replacement part that would fit so I bought a pair of trailer hub dustcaps for $1.99 from the local trailer parts store. They were way too small so I wrapped them in many layers of duct tape. I then coated the inside with a good layer of silicone sealer and really jammed them in place. I will let the sealer cure overnight and will report back tomorrow.