Different design to mine which you will see also has overriders. Could be because it has to accommodate 7" wheel rims.
![[Linked Image]](https://i.imgur.com/l0Kx564.jpg)
The current (all) Classics parts book lists only two, with and without side screen stowage.
ETA: BTW that knurled knob which can be locked tight, has a retracting locating pin on the end. When wound out the adjacent portion of the rack pivots forward and downwards allowing side panel bag to be slid in sideways from the right hand side.