Random Dart Parts ID Please

Peyote,
Look in the factory manual AC section. I was looking at my 64 manual yesterday and noticed that B-body AC cars had vacuum controls (like my 65 C-body), whereas A-body AC was an under-dash box. By 1966, they must have moved AC to the dash w/ similar vacuum controls. You can download the manual free on-line (recent post).

I'll take a wild stab at the two hanger bolts. I'll guess they supported something hanging under the dash. While we are focused on AC, I'll suggest the long thin AC vent that hung under the dash. At least it did in my 1969 Dart w/ factory AC.