How do RCNC.

Nope,that wouldn't do,ye see the saddles carrige has two items in the way ie the gear that tracks along the rack and then the half nuts to engage with the leadscrew for auto feed.

I'm stumped as to how it works?

7th pic down shows the protection,although this saddles apron is different to the C2/C3....
http://www.toolsandmods.com/apron.html