For a new face, yes. Because your season is now embedded in a SAV file. But if a player has a certain number, like Matt Cain, if you input (or even make a new) Matt Cain face with that very same number, it will show up in your present season because the on-going season draws its faces and all else from the models.big file.
No, there is no way that I know or heard of to alter a SAV file.