Yes and no. [spoiler]While the Guilty Spark we know was killed on the Ark by the Chief, a highly corrupted fragment of Spark, the "human" part of him was left and discovered by UNSC scientists. The fragment contains memories of Chakas, 343GS' human form prior to his transformation into a monitor by means of a "digitalization" of his mind at the hands of the IsoDidact. While 343GS as we know him is dead, the fragment that contains his memories, while not intact, is alive. Greg Bear's [i]Primordium[/i] can help shed some more light on this, if you are still interested.[/spoiler]