The early "Lost Cut" of Star Wars contains the part described in the novelization (based on the shooting script) where Luke, having finished repairing Threepio's arm, goes to re-attach the restraining bolt, then decides not to when Threepio winces noticably. This implied that Luke not only trusted Threepio, but was starting to think of him as more of a companion, and not simply a servant. Apparently this was discarded when the film underwent a complete overhaul during the re-editing process and the scene in Ben's house was rearranged (which is why Threepio is awake in some shots after already having shut himself off).
The version of the film I was referring to is the rough assembledge of footage put together by the original British editor, John Gympson, before he was let go by George Lucas. This first cut of the film is commonly referred to as the Lost Cut. There is a comprehensive article about it in issue 41 of the Star Wars Insider magazine. The scene with Luke and Threepio is discussed on pages 42-43 and includes a photo.