Just brought home my 2014 Silverado and I am strarting to learn about the differences between this truck and my 2003 Silverado. I noticed that there are six openings in the bed, directly under the bed rail. The openings look like they could allow salt to enter from road spray in the winter. Was this an engineering change to allow for moisture to escape? Should I even be concerned about the openings, or seal them off in the winter? I only ask because my 2003 Silverado rotted (rust) out the rear wheel wells.