66 Slant AC Harmonic Balancer question

The pic you posted is the knee knocker style that was dealer installed. Being dealer-installed, they would have used all factory hard parts to the greatest extent possible - compressor, drier, condenser and some of the hard/hose lines.

If you have PS then you will have 2 bolt on pullies- one behind and one in front of the balancer with the pulley for the alternator. I’ve seen several with aftermarket knee knickers and no PS use the front PS pulley on the front.