In theory simply spring-lifting a CJ shouldn't change caster, assuming the springs have the same eye-to-eye length as factory and you don't change shackle length.
Many of us have used YJ springs for our lifts because they are 2.5" wide in front and provide a better ride. However, the front YJ springs are about 1" longer then CJ springs. Therefore caster angle does change when using these springs.
My 2.5" YJ lift required 4 degree shims to get 7 degrees of caster. It tracks and returns to center beautifully with this setup.
Hope this helps,