A Man Called Sledge

Outlaw Luther Sledge and sidekick Mallory pull into the town of 3 W for an overnight stay. While Sledge heads upstairs to spend the night with long-time prostitute friend Ria and a bottle of rye, his sidekick Mallory enters a game of poker downstairs in the saloon. Frustrated with loosing their money to Mallory, two of the other gamblers shoot him dead. Alerted to the downstairs gunshot noise, Sledge descends in the saloon, pretending he's drunk, catches the two gamblers unprepared and shoots them dead. An old man who witnessed the shooting offers to serve as Sledge's witness and swear it was self-defense in case of an inquiry. The next day, Sledge leaves town to meet with the rest of his gang in the hills. He notices the old man from the saloon following him on horseback some distance away. Sledge stops the old man and asks him why he is following behind. The old man explains that he is not following Sledge but rather a convoy escorting a gold shipment. Interested, Sledge takes him at the meeting with his gang. There, the old man explains that while serving a 20 year sentence in the Rockville maximum security prison he learned about the existence of a vault inside the prison where gold is kept overnight. The gold mes in the region ship their gold under heavy armed escort to the prison where the gold sits in the vault overnight until ready to be taken to the gold exchange in the city. The escort is comprised of 40 hand-picked armed guards and the gold wagon is equipped with a manned machine-gun on top of it. Attacking the convoy would surely mean suicide. The old man insists his story is true and that he was imprisoned in a cell adjacent to the bank-like vault deep inside the prison. Only six inches of steel separated him from the gold kept in the vault. At this point, Sledge realizes that attacking the gold shipment and its escort wouldn't be feasible. However, the old man's story gives him the idea of breaking into the vault inside the prison where the gold is stored overnight before being taken to the city. Sledge shares his plan with his gang and reveals his plan to pose as a prisoner in transit being escorted by a marshal to the Rockville prison for an overnight stay until the next day when the marshal would take him to the jurisdiction that posted the wanted bond for Sledge. A member of the gang, Erwin Ward, agrees to impersonate the marshal and Sledge agrees to play the captured outlaw and use his real name since he's wanted for a 5000 dollars reward anyway. Will the plan work ?