Walter Koenig, Star Trek’s Chekhov, has a mantelpiece loaded with action figures, ranks of them. Earth-2 Flash stands out. Koenig was already 20 in 1956, when the Flash got revived. His autobiography makes no mention of superheroes or comic books.

In other words, it’s a mystery.
Sources: How William Shatner Changed the World, directed by Julian Jones; Warped Factors: A Neurotic’s Guide to the Universe by Walter Koenig