Well, I don't want to assume because that's what got my foot stuck in my mouth at the beginning of this thread. I'm going to say they both have the same amount of protein.
Bingo
So, just so we can take this through to it's conclusion. Lets say I have a raw chicken breast that weighs 8oz. If we assume 7g of protein per oz then it's 56 grams. The fact that it cooks down to say 5.5oz is not relevant. It still has 56 grams of protein. No nutrients are lost in the cooking process? Right?
Yep. Well, some of the fat will likely cook off but as chicken breast has minimal fat anyway I would worry about it.
So I've based my diet on eating 6 oz of cooked chicken. Which was probably 8oz raw. So I need to redo my protein macros for the day
TBH, if you are always eating the same amount and cooking it for the same length of time each time then I wouldn't sweat it. It'll be such a small difference each time that you could just go with doing it how you are. But, yes to be more exact (anal), then weigh before cooking.