Early 28 orignal light switch help

[firechief5215]

I have 4 pictures of our light switch that came off our early 28 (FEBURARY) fire truck, Some time ago this setup was taking off and they rigged up a different setup. I have been able to come up with these parts but I am not sure if I am missing anything . I have the original doomed cap also that is not in the picture , I laid them out the way I think they should go but I am not sure, Also it has a plastic flat disc I believe was made a lot later to strength the disc that has been repaired.Shoud there be some type of spring in this like the later style. Please help us with any information and pictures you can help us with also Is there any parts available for this and is there anyone who makes the correct wiring harness for this fire truck Sorry for a long post but im trying to give as much info as I can
Thank you for all your Help Billy