If you only ever look at one side of a cube, you'll never know that it has six faces. Are you being narrow minded this time? Try turning this problem over and look at all its sides.
We all judge books by their covers. It's inevitable and it's very human. What really matters is that you give the contents of the book a fair chance. You've judged someone by their cover recently, and now you're beginning to wonder if it was premature. Was it the right judgement? This is a good time to take a peek under the cover, turn a few pages, and see if there was any substance to your judgement.
Whether you need it or not, it's always good advice to keep your resume up to date.