Curious about Apple giving a new/refurbished phone if they messed up the battery replacement

I've been seeing posts before that Apple will just give you a new device if for some reason they broke something in your phone while replacing the battery. What if your phone is red, blue, or green, etc.? Do they make sure to have the same color before doing the service just in case replacing the whole  phone  happens? Or are they just going to offer midnight or whatever they have, and you don't have a choice? LOL