I was told in this answer to another question: "The Rambam did not take the '6 days' of Bereishis literally, as well as other details." The answer linked to Moreh Nevuchim (link) but I couldn't find on that page where he really said that it wasn't in six days. In fact, it was my understanding that Rambam and others did take Masay Bereishis as happeneing in six 24 hour days, although I don't know a specific source. What does Rambam say on the issue in Moreh Nevuchim and elsewhere?
In a broad sense the answer is no, the Rambam did not take the six days literally: “First, the account given in Scripture of the Creation is not, as is generally believed, intended to be in all its parts literal.” ( Guide for the Perplexed 2:29, Friedlander page 211).
Precisely what he did view is complicated by the fact that he believed the topic was esoteric and under normal circumstances prohibited to be committed to writing.
The Rambam's view, insofar as I can tell, did not necessarily preclude a literal six days or an interpretation that was "literal" in a very broad sense. His interpretation, as I can tell, seems to predicated on a number of key words not being understood as they would be taken on first impression but instead given a philosophical definition. In a sense I think you could make the case that the Rambam did not reject the plain meaning but what he viewed as an over simplistic reading.
Along these lines the Rambam defends the plain meaning against Aristotelian philosophy (2:17) prior to giving his own interpretation. And remember the Rambam explained that, “a mere argument in favour of a certain theory is not sufficient reason for rejecting the literal meaning of a Biblical text.” (Guide for the Perplexed II:25, Friedlander).