Yes, that's usually how it's done when those bushings go bad. Not only because it is easier and less time intensive to replace the whole wishbone assembly than to press out the old bushings and pack the new ones in (you spend more for parts and less for labor, basically), but also because the receptacle on the arm containing the bushing itself may be damaged / deformed. However, as you can see in the CPO document's list of covered part, control arms are only covered by the warranty if they are found to be defective, not because of a serviceable bushing needing replacement...