Welcome to The Stovebolt, johnni!!
The 1-1/2 ton front fenders have a larger wheel opening than the 1/2 ton. However, it isn't that easy to spot when they are laying on the ground at a meet.
Another way to tell the difference, which is better, is that the 1-1/2 ton fenders are not notched for the bumper brace to bolt to the frame and the 1/2 ton fenders are notched for the bumpers braces. That is probably the best way to tell the difference immediately on sight, but I have seen some 1-1/2 ton fenders notched and used on the pickups.
Last edited by 6cylindersovertexas; 02/19/2011 6:17 PM.