Unlockable: Reed's armored horse and Macgruder's cannon shotgun
Finish story mode and all side missions for 100% completion. Then go to Macgruder mine to pick up your rewards.
Unlockable: Apache Shirt
Finish the Hunting Missions.
Unlockable: Silver Spurs
Finish all Pony Express Missions.
Unlockable: Dual Peacemakers
Beat Hoodoo Brown.
Unlockable: Cavalry Sword
Beat Reed.
Unlockable: 69 Ferguson Rifle
Beat Hollister.