No, for me overclocking has never been necessary, and thats on a worse computer than what I linked for you.
Have you ever put a PC together by the way?
But back to your question, I do not recommend overclocking to first time builders, its a fairly precise process, and you can screw something up if your not careful. Over clocking can be a great way to get some extra FPS and performance out of your components, but I wouldn't do it unless you feel like your game play is suffering and it may help.
IF you decide to try overclocking, I'd definately do a lot of research and tutorial watching before you try it.