Help with rotor thickness

[SicC10]

Ok guys I'm trying to order my drop spindles. I went out and measured my front rotor thickness and they are 1 1/8 thick. Thought they were just 1 or 1 1/4? Also do the hd 1 1/4 make that much of a difference?

[NorthernMainer]

Look at the build tag in your glove box if it's still there, that should tell you what you have. I want to say JB3 is the 1" thick rotors, and the JB5 is the 1.25". You should also be able to figure it out by the gvwr of the truck. 4,600lbs will have the JB3, and 6,400lbs will have JB5.