Ah, so that's what the welds on the base were for. I was planning on just running a piece of threaded rod or a super long bolt through both of them, so it would basically be the same setup as the swingarm bolt holding the front in. Think that would work?
Nvm, I think I see what you are talking about. Are they the little plug welds (not sure of the technical term) close to the outside of the spacer?