He is selling them, not sure why you would think otherwise...
1.5 lets you not do any other mods. My 1.3 spacers requires barely grinding down the rear studs. You do not get into the stud threads at all. I have been thinking of going to a 1 inch spacer since you will still get full thread engagement on the lug nuts. Just hard to justify the cost for .3 inches.
Also with spacers you can get 12 mm studs like stock or 14 mm studs like the 1/2 ton. Not sure what Colorados came with. Email mark at markmcmaster2003@gmail.com and he can tell you what he can do for ya.