>>54836872You'll need to know your SID to get a shiny, which can either be manipulated at the start of the game, can be calculated after finding a full-odds shiny, or can be calculated by transferring any Pokemon with your OT up to the modern games.
You'll need a specific SID - and will have to restart your save file - if you want to catch or receive a shiny with 5 or 6 perfect IVs, though this restriction does not apply to eggs and bred Pokemon.
