A.C. Cars fabricated steel brackets, painted them chassis black, and attached them to the floor and front wall of the footbox. CSX2001-CSX2200 used a Lucas brand dip switch and appropriate hole pattern while CSX2201-CSX2589 used a Ford switch and a hole pattern appropriate for it.
This is not a great illustration but it was cut from a factory picture taken at A.C. Cars in mid 1964.
If the switch is used for a foot rest the switch will get clicked a lot, probably many more times than designed to deal with.