What size do you need for the cover? My ace hardware has SS hardware and a special bin of chrome automotive dress up hardware. There are many stainless steel specialty suppliers online. Fastenal, totallystainless, among others. Not too many odd sizes or fine pitches on old trucks. Just maybe the spindle and some suspension threads, but they are all rods and ends. I won't even ask why you want stainless on a rear end cover.

Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn