Hogue makes several different types of grips for the PT 92 - rubber, wood and aluminum. None of the grips Hogue makes for the PT 92 require different screws. While they are very attractive, I do not find the aluminum grips to be as practical as some of the others, and due to the inability of the material to deform slightly while the grip screws are being tightened, grip screws tend to vibrate loose during firing.
Pachmayr's signature grips are of the wrap around style, and have an optional provision for rubberizing the back of the grip. Pachmayr's grips add substantially to the overall circumference of the grip, but the soft rubber and design of the finger grooves allows for a very solid grip on the gun that does well under rapid fire. These grips work best with grip screw bushings (part 5.3) and the "top left" grip screw (part 5.2) or Beretta bushings and grip screws.
The parts are not available from Taurus online - you'll need to call them. The grip screws are part number 5.2 and the bushings are number 5.3 - you will need 3 of each, although at the price they're offered at you might want to get a couple extras.
Taurus' customer service number is (800) 327-3776 and they are available 9am-9pm eastern standard time.