Yes I was aware of the angle strips and location of cross sills. Was not aware of the rear cross sill. Does the rear sill bracket force the bed to sit higher than the 57-59? With the 57-59 cross sill I have 1 1/4 blocks clamped to the frame. Did put up a fender and running board today and it looks OK, but did not check the other side in case the bed sides are mismatched. Thanks for that advice.
Cut off old bed brackets and they are not redeemable. Did not see the brackets on the Mar-K website. You suggest I should look closer?