Did you figure out the deal with the bushings? It looks to me like he should have kept those because they are needed to act as a spacer for the three-point arms when the mower brackets are NOT installed. You should already have a pair on your machine. If you look at the attached pic, you can see that those bushings are removed when the mower bracket is installed.
"Wow, those brackets sure hang low."
Yeah, that's one of the reasons I use my rear finish mower more than my belly mower, all that stuff needs to come off to do much dirt work or mowing in the pasture....