Looks like they've verified the guy went to school with Spicer too, and was a year below him.
Reviews of the book are

.
"Mr. Spicer has not been well served by the book’s fact checkers and copy editors. He refers to the author of the infamous Trump dossier as “Michael Steele,” who is in truth the former chairman of the Republican National Committee, not the British ex-spy Christopher Steele. He recounts a reporter asking Mr. Obama a question at a White House press conference in 1999, a decade before Mr. Obama was elected. There are also some omissions: He writes about working for Rep. Mark Foley (R., Fla.), who he says “knew how to manage the news cycle. And on top of all that, he was good to staff and fun to be around.” He never gets around to mentioning that Mr. Foley later resigned in disgrace for sending sexually explicit messages to teenage boys working as congressional pages."
"Aside from the Foley thing, these errors just make Spicer look like the idiot he is known to be—though he’s such a well-documented liar that you can’t help but wonder for a just a nanosecond that he’s on some weird, deliberate campaign of deception.
According to Karl, Spicer also continues his habit of debasing himself for the benefit (pleasure?) of President Donald Trump, calling him at various points a rock star, the Energizer bunny, and even “a unicorn, riding a unicorn over a rainbow.”"
https://splinternews.com/sean-spicers-new-book-is-apparently-littered-with-dumb-1827828511