Maybe yes, or maybe not :)
Next to the fact, knowing the truth about Atlantis, its not neccesary at all, this is an exciting topic :)

And its also a fact, the level of see was much higher a long time ago, so its not impossible, the richat structure was the original Atlantis, when that part of Africa wasnt the current continent, but a separated land. I dont know, but its possible.

Actually we dont have enough maps of the oceans, so we dont know, what can be there in the deep. Maybe more ancient cities :)