The good news is that the glitches are still present in RBY; I have personally managed to test and confirm the Instant Text Trick (saying no to the Bike Shop owner allows instant text until the next time you open the menu or switch Pokémon in battle) and the Mew Glitch via the early Cerulean method (need more Poké Balls to catch that thing though).
Yeah someone posted about this already but consider this personal confirmation of those two at least and by extension, the other glitches in the game.
Yeah someone posted about this already but consider this personal confirmation of those two at least and by extension, the other glitches in the game.