If that were my truck I would do a u-bolt flip, make my own 1/2" top plates for about $10, make my own boxed in 1/4" wall perches for about $20, and get some 9/16" u-bolts for $50 at the local spring shop along with new center pins for $5. You can toss those crappy (aluminum?) shims when you weld on new perches.