I am also a fan of the Unleash The Archers cover https://www.youtube.com/watch?v=XRD3vrSLPaw

It’s both. In episode 1 someone asks the cowboy actor to “do the thumbs up”. Later, the actor explains the mushroom safety part to his daughter. In episode 3 there is another flashback where the cowboy actor does a photoshoot for Vault-Tec. He asks the photographer “what if I try a thumbs up?”