rings/sleeves on upper control arm bushings

I'm in the process of replacing the dried out rubber bushings in the upper control arms. Pressing them out, I noticed that each side on the rear bushing, there was an extra sleeve/ring/collar that was on the bushing. What was the purpose of this and why were these on the car? Did all cars get them?

Car is a 69 RR.

Most all the cars except 6 cly got those from the factory. It helped to keep that one bushing in because it had more force trying to push it out while in use. Most techs destroyed them in trying to remove them so you seldom see those reinstalled. Someone makes new ones.

FSM page 2-11 fig. 16 shows it's used on A bodies with 10" brakes.

I have an early set of a-body arms that still have them.. I also have a later big ball joint a-body set that did not have them. However someone else could have removed them years earlier.

If the inside and outside diameters are a common size you could buy some pipe and make your own.

https://www.forabodiesonly.com/mopar/threads/upper-control-arm-bushing-extra-part.430450/

They were for fleet vehicles, taxi/police, etc.

My 70 Charger R/T had them as well as my brothers R/T.My Charger 500 did not.

Interesting..... so really no rhyme or reason as to why they were installed.