Bigdog is correct, it's your truck to do whatever you want with it. As for military weapons, I'm a collector of militaria and have 187 military rifles and handguns from WWl through Vietnam. They are all original and I would never think of modifying them in even the smallest way. My opinion is to leave history alone. They all have a story behind them. Every rifle has the proper bayonet and sling that go on the rifle. Ammo and cleaning kits also.
militarypotts Spec/4 Military Police, Vietnam Era, "Does the noise in my head bother you? Welcome to the Twilight Zone!"