That is for the most part, correct. GMC did use Spicers pretty much exclusively. With Chevrolet, though, it depends on what the options were. Generally speaking, 3/4 ton coil spring trucks had the Eaton, and leaf spring trucks got the Spicer, which is how GM lists them in the specs on the Heritage site. However, I have heard of sightings of leaf spring Eatons and coil spring Spicers. Also, GM does show a listing for a 1/2 ton with the Spicer rear and coil springs, but only with the 396 engine.
