Yep you got it. I want the rail cap/covers. I can see from the inside views you posted that the original parts are injection molded with slides (slides = $$$ in mold tools), but they could be built with 3D printing and/or stereo lithography then cast for the small quantities our VX family needs (ie < 10,000). Mine are currently nekkid (I have no crossbars on my rails, nor do I need any currently).
Also: cute teddy bear
Edit: I would think also that color coordinated rail covers would be cool too. I would put silver ones on my Astral!