I assume your truck is 2wd because the studs are too short.
You need to get the 4x4 bolts from the dealer/junk yard, they are much much longer.
this is a double sided stud, one end retains the radius arm to the beam and the other end the coil retainer.
They are a real bit&* to get in and out of the beam, be prepared with 3/4" drive impact or long breaker bar, liquid wrench, and a DEEP socket
You will also have to get an alignment after you install the spacers and the alignment will most likely require 3.5 degree (2wd) camber correction shims, so you should consider installing those at the same time to save some $$$.