Hey guy. I passed on responding to your post a few hours ago because typically at least one of the Pedder's reps is by here every few hours even on weekends.
As Joe GTO Owner I have no idea who has what in stock.
I have yet to ride in a Noltec equipped car. The folks that have like Noltec way better than stock bushings. I own a partially Pedderized GTO, and I like Pedders way better than stock. I have yet to ride in a Super-Pro equipped car, the folks that have Super-Pro like them way better than stock GM.
I am sure you can see the pattern.
In my opinion the three bushings that should be changed on even garage queen GTOs are the front radius rod and rear X-member bushings you have already named, plus the front strut top bushings.
This is a link to the knowledge base (KB) area of this website, specifically the suspension section: http://kb.ls1gto.com/KB/?cNode=7T6C7G . The various articles will give you a good idea of what is involved so you can make your own decisions regarding driveway DIY v- professional install.