Hey Mike 1911. Pics of the PIAA mounting brackets.
This is what it was originally. The center hole for attaching the light was a small machine screw... which was too small for the lights I had mounted. The 2nd pic below shows what I did... I drilled them out with a 3/8" bit so I could get a bolt through there.
Also, the first pic shows the mounting hardware it came with... which I no longer have. The main thing you'll need is an expansion plug that you can screw into and a neoprene or rubber washer for a little vibration isolation (which I guess it was for).