Interesting that the bars were installed the wrong way around at the back. But correctly at the front. The design enables the bars to be dropped from outside the trailer in the event of an accident whereupon the fall own. This requires the bars to have the straight pins on the outside walls and the curved pins on the partition. It is especially important for the front bars to be installed this way (which in this demonstration they appear to have been). If a horse somehow gets its front legs over the best bar it can be dropped from outside the trailer by winding the bolts out which support the bar attachment.