As mentioned, talk to White Brothers! About a year and a half ago, I sent my SC90 fork to them, as I was preparing to move it from my daily rider to a special restoration project. They not only did a complete service, but they actually removed the 1 1/8" threadless steerer and pressed-in a 1" steerer for me. Really amazing customer service, if you think about it. (That, on top of a quality product that has served me well continuously since 1997!)
FYI, the modern dust seals that they installed, at the top of the lowers, look a little different than the original. They're all-rubber, instead of rubber with a spring tensioner. Makes me think that they've either made some new ones, or that that the fit specifications are common to some of their newer forks, and that they will have them available for a while.
You can kind of see the seals in the attached photo.