Anti Squeak pad between frame and springs?

[TBone69]

Hi Folks

In the tear down process of my Model A chassis I found remnants of some sort of insulator pad in the rear spring pocket in the crossmember.

I've looked in the catalogs but don't see this listed.

Guess my question is, Is there supposed to be an insulator of sorts between the front/rear spring and the frame?

If so maybe I am not looking in the right place for this part. I'm putting together a list for a parts order and want to make sure I have what I need to start reassembly.

Thanks
Tom