No not really. The story was pretty much universally considered to have been invented by Plato, because it was. There is no non-Platonic tradition of Atlantis attested (which is important, because to refer to the "Atlantis myth" as, well, a myth is very much wrong), and we know that the basic story was parodied by later authors. Theopompus' Meropis story is the most famous of these parodies, and intentionally takes everything that Theopompus found absurd about Plato's story and makes it even more ridiculous. Plato's story also did not totally come out of left field. The use of philosophical allegory is a well-known technique of Plato's--the story of Atlantis only lends itself to misinterpretation because it's supposed to have descended from Solon. But of course that in and of itself is a well-known Platonic feature, since Plato quite frequently distances himself from whatever's being said by having his characters claim to have heard it from a guy who heard it from some other guy whose sister is married to this other dude who once roomed with this one guy. In this case, the use of Solon and seekrit Egyptian dokumentz probably lends less credence to the story, despite the claim to a (at least theoretically) respectable source--in a discussion of ideal states, who else would an Athenian, and especially a Platonist, use to support his claims than Solon, the lawgiver, and Egypt, which by the time of the Timaeus was already the prototypical ideal state in Platonic thought? A few later authors used the Timaeus as the basis for similar discussions of states--Euhemerus, for example, took much of the imagery from the Timaeus in describing his fictional Panchaea. In late antique authors Atlantis is universally considered to be an invention of Plato's, and one Byzantine commentator actually thought that Plato had taken the story from the Old Testament's report of the Flood. There is one passage known to me in which Atlantis is treated as something perhaps more than a Platonic invention. Strabo quotes Posidonius as saying that perhaps we should consider Atlantis to be something more than a Platonic invention, since in the Timaeus it is claimed that the story descends from Solon and Egyptian texts. Strabo, and apparently Posidonius, treats this as something like a thought experiment rather than a realistic possibility. He finds it interesting, but the point seems to be an inquiry by Posidonius into what constitutes sufficient evidence for questions of natural philosophy. He does, however, seem to ultimately think that the Atlantis story does not predate Plato, and this was the general reaction to the Timaeus in ancient authors, let alone question of whether Atlantis was real--that is really a feature of modern, particularly Victorian and early 20th Century, thought, often connected quite consciously to the neo-pagan and mystical movements that arose during that time and often to explicitly racist ideologies