Regarding the brackets - first pic here is a 1971 without a/c, but in the notch if I'm not mistaken sits an emissions line. I'm not really up on all the details on the 71s but I think they all had this line? While in 1970 only cars with California emissions would have a similar setup here, federal emissions just a dimple for the screw that would hold the line clamp, and the water valve is mounted further down regardless of CA or federal emissions. For 71 it seems to be the same - did they change the shape of the bracket to accommodate another difference in the inner fender? The repop valve brackets are listed as fitting 1970-74.

Second is one with a/c and the emissions line but no notch in the inner fender, maybe a 1970 with CA emissions.