My unequal length bars do not use the horse shoe style bracket, they use this:
When I get home from work I will post a photo of the mounting bracket on the bottom of the bar. Also, looking at ChevyandPontiacs pictures of his bars it looks like his similar style bars are also different length. One last note, somewhere at home I have a 1969? Lakewood Catalog which shows the bars with the straight bracket shown in the photo here. If I can find the catalog I will post it