Welcome to the forums!
The lock you have was used from 70 to 77, I believe. Removal is fairly simple. You have the interior handle off and the interior locking knob simply unscrews. You then have three screws on the interior side of the door and one screw that is located in the door jam.
BTW, be careful with the lock, it is pricey!
WBCCI President 2016-2017