Odd looking hardware.........
It looks like the top picture shows the 'front door' on the left side and it still has an adjustment screw of some sort, yes?
Usually, as you may know, the 'front' door of the pair has to come off first, by tilting the bottom out, and then lifting the roller off the top track. However, it looks like you've got a bottom roller guide as well, yes?
The bottom ones look like they're spring loaded to keep constant tension, so there must be a way to grab them where they can be compressed and removed.
I have no clue if I'm helping you...........but I love a mystery!