When I changed mine, none of the bolts that came with the installation kit I borrowed fit, and so I was forced to use the original bolt for the re-install, and it worked just fine. Although, I am sure you are better off with a longer one, as you are pulling it on with very few threads at first I do believe. It helps to slather everything in motor oil to ease the installation.
I bought a longer screw, then had to use a couple of metal standoffs and washers to make contact with the screw's head. Got it on and now I'm rollin' (just gotta screw down the part that covers the radiator and includes the hood latch). Thanks all!