Technical 1950 Chevy Horn button hardware

1950 Chevy Styleline Deluxe Sport Coupe.
Just bought this and it has an aftermarket steering wheel on a tilt column.
The original steering wheel is in very nice condition so I would like to put it back on.
The horn center does not snap on tight. I think something is missing. It has a Horn Pivot Ring (Plastic) and sort of a snap ring, below that is the spring piece of metal that contacts the brass/ copper horn contact. What is missing?

 

Should be a wire circlip around the base of the cap. There's a groove in the wheel where it snaps in. If the wire is there, maybe the person that painted the wheel filled in the groove. That's a '49 horn ring ..

 

Check with Chevs of the 40's. Seem seeing a small parts kit for your application.

 

I found several indentations (grooves) in the inside but not all the way around. Should the groove go all the way around ? Other wise seems it would need to be an odd shaped retainer wire/clip.

 

https://www.classicchevy.com/1950-1954-chevy-horn-contact-kit-80-244346-1.html

https://www.chevsofthe40s.com/dept/Electrical/cat/Horn.html

http://chevy.oldcarmanualproject.com/miscellaneous/1951horn.htm

 

I have the first item complete.
When I follow the link on the second part it does not show that part available, is that what holds the center cap in place ?
The 3rd pic does not show using the second part in the illustration.