Ammeter Battery overcharge

From what I can tell your 67 has the early regulator, alternator system. The early alternator has one field terminal connected to the alternator case marked ground. The other field terminal connects to the green wire that goes to screw lug on regulator. The early regulator conducts voltage to that terminal when IGN terminal is below about 13.8V, and not when above. It chatters about doing that at a fast rate. In your case of over charge, the transistor is shorted on ... and that is permanent.

You need an early style replacement regulator. The later style regulator shown in your first picture works by pulling the field terminal low to ground, and with a late alternator, the other field terminal is supplied by IGN. If a new style regulator is used with old style alternator, one field terminal is ground at alternator, the other is grounded by regulator, so field is never energized, and alternator will not function.
The picture of the spare alternator looks like the field brush terminal is broken off. Fix that by easy brush replacement, if you ever need to use.