This is a close up of the screw side. The OEM part has a chamfer here and observing the location before removing it revealed why. This side rides right up against the fixed support slide rail anchored to the fixed walls with little clearance.

This was the first end cap I made and chamfered it just a little too much, thus the steel finish washer to help build it back up. With this washer, everything sits perfectly and provides a little extra support in a potentially weak area.