In the film's official novelisation, it was removed slightly later, right before Luke received the lightsaber from Kenobi.
“You see, Luke, that’s where your father and your uncle Owen disagreed. Lars is not a man to let idealism interfere with business, whereas your father didn’t think the question even worth discussing. His decision on such matters came like his piloting—instinctively.”
Luke nodded. He finished picking out the last of the grit and looked around for one remaining component to snap back into Threepio’s open chest plate. Locating the restraining module, he opened the receiving latches in the machine and set about locking it back in place. Threepio watched the process and appeared to wince ever so perceptibly.
Luke stared into those metal and plastic photoreceptors for a long moment. Then he set the module pointedly on the workbench and closed the ’droid up. Threepio said nothing.
A grunt came from behind them, and Luke turned to see a pleased Kenobi walking over. He handed Luke a small, innocuous-looking device, which the youth studied with interest.