C4AFDG Autolite 4100 question

[tdyltc66]

Hi guys, I am completely new to this forum and this is my first of what I hope will be many posts. However I must confess that I am not a Shelby Cobra owner, although I would very much like to be. I own two classic Mustangs: A 1966 200 c.i. 6 cyl. 3-speed convertible and a 1965 289 c.i. 271 h.p. hi po 4-speed coupe. I hope that this does not disqualify me as a member of Club Cobra. The subject of my post concerns the 289 hi po car. I am in the process of rebuilding the C4AFDG Autolite 4100 carburetor. I have two questions:

There are two small, what appears to be, brass pieces; flat, 1" X 1/2", with holes in the middle. The vertical manual choke rod that activates the choke plate passes through the holes in these brass pieces. As far as I can tell, these pieces of flat brass serve no useful purpose; other than to bind up the choke rod. does anyone have any idea what these things are and what, if anything, they do?

Also does anybody have an opinion regarding the need, or lack thereof, of a check ball in the vacuum secondary circuit? From what I have read these elusive check balls are absent more often than they are present. My 4100 did not have one.

Any thoughts would be greatly appreciated. Thank you. tdyltc66