It should just prompt you to change their stats or leave them how they are. I think we need to be able to customize their stats as companions often have wasted stats and are already screwed up for any good builds by the time you find them.
Just to be a bit nit-picky, changing stats would be a bit annoying if you couldn't also change skills. One solution to this could be that companions don't start with any skills, but they have some money (150 or so) to buy some. But I think it'd be better just to have the character creation screen and let the player choose 3 skills there.
