What Mike said. When I got my used rails, they came with almost no hardware, so obtaining it delayed the install. You can reuse the existing bolts (and I cannot remember which exactly, I think those to the exhaust hangers/rear peg mounts), but the rail mounts mean the stock bolts do not tap to full depth (by like a quarter/third inch) and this decreases strength of the setup. When used with proper hardware, the rails can be jumped up and down on (with the bags off). The mount underneath the bags require two round collar spacers, and even the original bag rail mount instructions (with parts list) do not include their length (again I can't remember but something like 1/2 - 2/3 inch). Finally, the little connectors for the rear bar around the fender are easier to install upside down, or backwards, from how the instructions say to do it. Also, the longer bolts needed should be chrome flange bolts to match everything else, but I could not get them anywhere locally, so I substituted stainless hex heads and washers, and you have to look very close to see the mismatch.
Finally, like most multipart installs, it will go best if you install everything loosely, then when it's all attached, go back and tighten it all up.
If you study the parts list in the rail instructions, vrs the OE parts lists you can find on line, you can discover the longer bolts needed (as well as the needed wrench sizes for the install).
http://www.valkyrieriders.com/shoptalk/Manuals/BagRails1.pdf 
