I'm getting ready to lower my truck and I want to improve the brakes at the same time. I have a 1983 ranger so I want to swap to the 1995 spindles. I know I need the later model lowered I-beams I currently have the Sporttrac rotors and Mustang GT calipers but how can I visually ID the rotors. They we're ordered at a local salvage yard and I don't want to walk away with the wrong pieces.