Betty White's character is told that PETA (People for the Ethical Treatment of Animals) would be interested to learn of her alleged mistreatment of her cows. In reality, Betty White is a major on-air spokesperson for PETA.
Sheriff Keough's "big gun" was a fake gun made specifically as a prop for this movie. They even gave it a fake name, calling it a "Light Weight Forward Area Air Device Unit" which itself is a pretty good parody of military jargon. It was not an M-203 grenade launcher, which fires 40mm grenades. The "grenades" shown with the gun were a good deal smaller than 40mm.