The phone that rings for Barry and Iris while they are in Nora's memory plays The Flash's theme tune played at the beginning of every episode.
Barry doesn't suit up as The Flash in this episode. Neither does Cisco as Vibe, Caitlin as Killer Frost, Ralph as Elongated Man and Nora as XS.
While it started out as a joke comic book writers found funny in 1959, the Flash Museum has become a recurring locale in the DCU throughout the decades. Besides the comics, it's also appeared in the 1990 The Flash series (in the episode Fast Forward (1991)), in Justice League Unlimited (2004), and Justice League: The Flashpoint Paradox (2013).
On the shelves of the Flash Museum gift shop are actual 6" figures from DC Collectibles.
This episode confirms that the Myles mentioned in the beginning of the season was indeed Dexter Myles, who in the comics was the curator of the Flash Museum.