Highly doubtful because when Revan was turned into a vegetable by Malak the Jedi when reconstructing his personality with the minor changes and such would have picked up on the memory of his young sithhood and probably wouldn't have let him out of the sight of the council. Also they would have never trained him as a Jedi again because that could bring back his origional sith training if we follow your line of thinking.
About the names, It just seems that because Revan and Malak were trying to follow an example without an actual teacher that they were slipshod in their teachings. thus we got the Darth *name* rather than the Extra title. Besides to call him Darth Revan keeps him away from the Darkness that is normally associated with things like Maul, Sidious, Plagius, and Treya. By the way Sion at least is a name not a title.
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