Wiper Switch Installation

Installing a wiper switch on classic dash insert for 68 barracuda.

Holes on both the classic dash and original panel are the same size.

Installed bezel nut on wiper switch, seems like switch will pull through the hole. Does this on both the original and the classic dash. I looked in my 68 service manual and there's really not much there. Am i missing a washer? Didnt not take apart, came in pieces.