Yeah, you only need the 1/4" NPT tap though. The other two and the 3 dies are not needed. But decent price on the set if you ever find a use for the other parts. Or you can go to Home Depot and pick up a 1/4" NPT tap and a 7/16" drill bit.
Also remember do not try and make one hole with the 7/16", make sure you make at least one pilot hole first. On hard plastics I like to use 3 smaller bits before jumping to the 7/16". Especially on acrylic. Acrylic will kick your ass if you try and do one big hole. You will crack the hell out of whatever your workign on. have to be very gentle with plexy and acrylic.