Basically when seeing it, say a starter, could you see if it is a shiny by seeing if the sprite is shiny? I'm also wondering for things like korrinas lucario
No, but there is one exception
The only time you can see if a starter (or any gift for that matter) is shiny is in HGSS. Korrina’s lucario is shiny locked.
Source:Experience (I’m an insane shiny hunter)