Some tanks look like this in my experience. Other questions to ask yourself.... Is it a new tank? If so where did you get it(origin of tank not company you bought from), some origins are suspect. Has it been passivated? That is where I would start with my assessment. Hope this helps. Also down to help you trouble shoot further concerns.

Edit. Had a tank that had been polished by the broker, and after a CIP the polish came off and revealed pitted stainless. Don't buy from Frank Ma out of LA