I am storing the Hollow Stone for later when I need to forge a Evolutionary Stone. Hopefully, that's okay. I didn't need to use it right away when I bought, right?

MP: Machop, Zubat, Girafarig, Zigzagoon, Swinub, Sudowoodo, Pinsir, Shellder, Magikarp, Pikachu, Muk, Glalie, Kyogre, Tropius

Question 1: Was the Mystery Pokemon Introduced in Pokemon R/B/Y?