You are correct it is a anti-rattle spring. Its not a return spring. At first it looked like there was a bushing pressed into the bracket that bolts to the bell housing. It turns out that it is not a bushing, it is the continuation of the spring that wraps around the starting pedal shaft. There can be some slop between the starting pedal shaft and the bracket, GM must of decided a anti-rattle spring was more cost effective than a brass bushing.
I was thinking side to side movement, but the spring takes-up the slop between the bracket and the pedal shaft/rod.
Attached photo is from a 1946-1948 Chevy car starting pedal shaft showing the anti-rattle spring.
I updated the photo in my last post with an attachment.
