Replacing UPPER trailing arms on G body

[Grayel]

I'm preparing to install aftermarket upper and lower trailing arms on my '84 Monte Carlo SS. I've eyeballed the lowers, looks straight forward. But after checking out the uppers I'ved got questions. When removing and replacing the bolt that holds the arm to the chassis, is there a nut that's tucked away? I can feel it but how do I get to it? There are bushings on the "ears" of the rear end housing, is there a special tool to remove and replace them? Thank you in advance.