The solid window sidecurtains were only very early, up to TS8636. After that (up to TS28825, which includes early TR3A), the rear window slid but the mounts were still the wedge type. I don't know that the frames were different between these two types of "wedge mount" curtains, but I suspect there is at least some small difference.
The later wedge mount frames (like those for TS13571L) are two pieces; the main frame with the mounts only goes around the window area. The bottom half is a separate piece, basically just very heavy wire (about 3/16" IIRC) that outlines the flap with the zipper.
I have what I believe are the original curtains from TS13571L (somewhere), but as I said I don't know they are the same. Most likely not exactly, as I think the channel has to be wider to allow for the sliding Perspex window.
PS, there were also two variants of solid window sidecurtains. Up to TS5255 the flap was attached to the body with Tenax fasteners; LTDs were used from TS5256 onwards. Until of course the Dzus mount curtains, which had no fasteners at all along the bottom edge.