71 Chevelle Pro-Touring Stage IV kit

I got my Pro-Touring Kit back in December and finally got around to a full tear down and at frame off right now. Frame is back from powder-coat and got the rear suspension and brakes installed. Just started the front install and going over the parts I have. I'm trying to figure out where a couple of parts go and maybe some of you can help. On the small box the part number is RTA-BK, there are 2 of these. Anyone have a clue what they are and where they go? The CPP instructions are a bit minimalist and while I have figured out most of it I can't tell what these are or where these go.

Attachment 2631

Replacement bushings for the rear upper trailing arms to the axle.

I am looking to get as minimum the stage 2 touring kit for my 67 camaro rs vert. I am cleaning/repairing the subframe and going back with new stuff. The g-mod has not been done yet. I have read some control arms fix and some don't. So do the CPP arms retain stock and need the g-mod or not? Don't want to do something if not required.