In Red Dead Redemption for the Xbox 360, there are a few t-shirts and an accessory you can unlock by either finding them in certain places, or performing certain tasks.
Red Dead Redemption Logo T-Shirt 1 – Open 40 chests
Red Dead Redemption Logo T-Shirt 2 – In a chest located in a burned down house, in Riley’s Charge
Rockstar Logo T-Shirt – Playing as Jack, you’ll find it in the attic in the house in Beechers Hope. You have to beat the game to be able to access the house
Sombrero – Shoot an enemy’s hat off his head. Easiest to do in Mexico since Sombreros are easy targets
