I think they do pat downs, I worked there last year and the security was heavily armed, with AR's. IMO i would leave it in the car or at home, to avoid any issues, But it is in N.H. so they might not care.
My last visit - the rescheduled race in Nov 2001, the security was tighter than bark to a tree...
Things may have changed since then. One thing for sure has changed since 2001- Kyle Bush will be shooting off his mouth in 2009, so maybe you will need a SD firearm!