A process PMS color will be in the ball park. But for a true PMS color it has to be printed as a spot color. If the customer is that picky and has the money it will be the only way to make them happy. Also when used on letter head, bussiness cards, envelopes etc, it may be cheaper than doing 4 color. I was a pressman for 25 years and have run into this more times than I care to remember!