It would not hirt to do what you say and put the bushings on cup facing the rubber on the 73 up. It will help the bushing life . It will also make the front end alot less flrxable and help handling. This was only done to alow more movement and a softer ride. The performance 73 up suspension they faced the rubber to give the car a firm suspension . Here is a pic of a 73 340 front suspension that was never taken apart since new. Notice the cup faces the rubber. newer kits tell you to face them away . the bushings are alot larger then originals .
regardless of what it says on any cup, i have, and will continue, to put mine on so the bushing is cupped. that is why my bushings last tens of thousands of miles