jsburton,
The problem with your 98 is the airdam. The opening of your airdam is 3" to the inside of your frame, so in order for you to mount them, you will have to cut a slot in the shrouding for the tow hooks to come out, also you will have to have a piece of steel that mounts to the frame to extend the tow hook out far enough for the curve of the hook to be out side of the bumper shroud. Your front bumper looks like the 99's.
Gerald and I went over this awhile aback to see if he could mount them to his truck. He didn't want to cut hole in his bumper.