Welcome to FSM. Always good to have a fellow artilleryman and helo builder join the ranks.
To your question. Fireball Modelworks has a decal sheet that includes 1 CAV and Garry Owen markings. They are great decals too. Check out the Helicopters Forum for lots of great Huey info and show us some pics of your model when you get going on it.
Gino P. Quintiliani - Field Artillery - The KING of BATTLE!!!
Check out my Gallery: https://app.photobucket.com/u/HeavyArty
"People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf." -- George Orwell