Is there a bonus for completing gta v story mode?

The verified evidence from Wikipedia focuses on the development and release history of Grand Theft Auto V, including its production timeline, teams involved, and initial platform releases. It does not discuss in-game bonuses, achievements, or post-completion rewards. Information about specific gameplay rewards or bonuses would typically appear in sections covering game mechanics or features, which are absent from the provided source. For accurate details about bonuses, checking official Rockstar Games documentation or gameplay guides would be necessary.