Here is an excerpt from my build showing what was done on the bracket to make it so it would mount properly on the other side, I also had some custom work done on the brackets to make them low profile in case you were wondering what the heck was going on
You will notice that once you drill the holes in the proper position on the bracket that the back up light assembly won't be in the correct position with the weep hole down so you fix that by grinding off the clock positioning nodule on the lense then rotate the assembly approx 180 degrees and the lense will be in the correct position with the weep hole down.
http://67-72chevytrucks.com/vboard/s...&postcount=115