Mark,
Don’t know if they are different front to rear but when I did my 02’ Marquis the front rotors had very little wear due to the fact that the brake cans on the rear were a little heavier duty than the ones on the front. If memory serves me correctly I think the rears were type 36, and the fronts type 30. The rears had more braking power, making it harder on the rear rotors. My rears were all heat cracked, requiring replacement. At these prices today for parts, I would inspect fronts to see if they are still serviceable. New pads on the front may be all that is needed. Also, there is a spring kit upgrade for the Meritor calipers, two per caliper, make sure you install them also. Hope this helps.