Stanchions changed slightly over the years, some have 2 damper holes and some just one. I don't know if the 2 way damping conversions need to have a particular stanchion type to work properly, but it's worth finding that (hopefully someone on here will know) out if so then you may need check what stanchion type you have, later ones fit early models provided both stanchions are upgraded.
It's also possible the stanchion length varied between models, which may affect the kit you buy, anyone know if that's the case?