There is a store in the PNW that sells used (some are new) chainsaw parts. They show a kit for the 028 side tensioner. The picture of the "kit" only shows two pieces, the ones with the gears on them. The p/n of the "kit" happens to be the first one that JOHNSOBRI posted with his list of numbers. They also list other saws that the "kit" fits as being the 024,026,028,034,044,046,064 and066. They don't state this kit as being a conversion so I'm thinking it's parts to replace the ones that are on a saw already equipped with this style, BUT, if those same parts do indeed fit all those other saws, it may make finding the parts you need off
of a donor saw a lot easier.