wrong uniform size?

Medium sounds just right.

First and foremost, welcome to able2know, and congratulations on selection for ascension into the ineffable heavens of your prospective employer. I feel sure that you can be switched at the orientation, to say nothing of the exquisite pleasantries that you may otherwise enjoy at the induction ceremony. Given that your height and weight are of such serendipitous happenstance [ 5 - 6 feet at a comely 150 - 170 pounds ] I fully expect to see you.

I'd get a large if I were built like you.

Just ask them to supersize it.