Note: In my original post, I inadvertently left out the reference for Craig's position. After finding it again, however, I discovered that the below views were expressed in 2013 and that now, in 2019, he seems to deny this position forthrightly. Evidently, the Darwinistic Worldview won his allegiance over the plain meaning of the biblical text and the intent of its author. He stood on the proverbial slippery slope and slid headlong into the eventual denial of Scripture's obvious teaching. Nonetheless, here is the reference for his below quotes, https://www.reasonablefaith.org/podcasts/defenders-podcast-series-2/s2-creation-and-evolution/creation-and-evolution-part-4
Proponents of the Old Earth view of Creationism have some 'splainin" to do. For those who haven't heard, the world-renowned apologist and Old Earth proponent, William Lane Craig, recently admitted that Genesis 1 actually teaches 6-literal days of creation rather than the billions of years that he still argues in his debates. He even went so far as to state that this literalness appears to be the intent of the book's author. Said Craig,
"I am actually inclined to agree with you that the days in Genesis 1 are intended to be 24-hour days. But I don’t think that that means that they are not metaphorical or that they have to be literal. I suspect that the use of the expression “it was evening and it was morning” is indicative that the author is using the notion of 24-hour days. And I’ll say in response to the Day-Age Interpretation, for example, that it doesn’t seem like he is thinking of ages rather than days..." Did you catch the key words? Notice his concession to the 24 hour days, "I am actually inclined to agree with you that the days in Genesis 1 are intended to be 24-hour days."
Then, "...the expression 'it was evening and it was morning' is indicative that the author is using the notion of 24-hour days...
Interpretation: "Despite what I believe the Bible actually says, I will continue to deny it and force modern evolutionary thinking into the text."
So basically, if it looks like a duck, quacks like a duck, and walks like a duck, Craig, by some stretch of the imagination coupled with his desire to appease the naturalistic consensus, calls it a dinosaur.
The good things we can take from Craig's admission are that 1st, he finally concedes the literality of the passage as the author intended, and 2nd, that other Christian "old earthers" cannot so certainly and smugly posit the non-literal interpretation of the Creation account without having to deal with Craig's conclusions. After all, he is the king of apologists.
The sad thing, however, is that despite his forthright admission to a literal interpretation, Craig and those of like persuasion, still insist on forcing godless evolutionary thinking into the literal Genesis account and thus revealing a desire for the applause of men rather than God.
Hence, they have some "splaining" to do.