Kenyon was later known as Kenyon Isomat in Charlotte, NC. It was sold to Z Spar which was a fiasco and left the country running. In a sense, it reimurged as Charleston Spar located in the building in Charlotte. It is also known as Sparcraft too. Not sure if you can locate that part there but it is a suggestio.
What I had to do in the past is get long bolts that fit the hole that were too long with the threaded end extending beyond the mast step , cutting it off and drilling a small hole in the end. If the bolt head portion was too big or in the way, I simply ground it down so it was not in the way. This was done as an alternate source.