The question if I understood correctly is when I have someone that I am interviewing, do I judge them upon first impression. The answer is absolutely yes. This is why, what you wear, and how you carry yourself is tremendously important. Along with the firm handshake, smile, and look the interviewer in the eyes. They really are important.
Dressed appropriately seems like such a common sense. But not so. I have interviewed folks walked in with wrinkled shirts, unprofessional attire or not clean shaven. It does impact tremendously my impression of them. They would have to have a very amazing interview to may be win me over again. Even though, I will question if someone cannot get this common sense correct, how good can they really be at their work.
Therefore, I will suggest always err on the safe side and better be over dressed than to be under dressed. But if you are not sure, you can always reach out to the hiring HR personnel and they typically can provide you with suggestions. Too over dressed is not good either but still better than be too under dressed.
I hope this info is helpful.