Swish Sologlyde leverlock brackets, Swish Sologlyde tracks were updated as long ago as 2005 to use leverlock brackets instead of the old style dovetail brackets. The track profile also changed. The old brackets were dovetail and slid into the track from the ends.
This is what they looked like
The glide hooks which the Swish Sologlyde tracks use are designed for separate linings on curtains so that they can be cleaned separately from the actual curtains.
NOTE sold in quantities of 1, photo for illustration.