I tried using the coin case glitch to shinyify my unowns but it always becomes the letter V. I would like to ask if there is another glitch to shinify unowns in Pokemon Gold without them becoming letter V?
Due to Unown's letter and shininess being determined by IVs in Generation II, Shiny Unown will always be an I or V in these games.
So yes, it can be an I, but only an I (Other than a V of course). It is just a matter of getting the right IVs.
Source: https://m.bulbapedia.bulbagarden.net/wiki/Unown_(Pokémon)