That's news to me. I would suggest you still try to get the discount after you sign up at no commitment. Better if you use your company email (if you have one) because you can apply online and it's effective immediately.
One warning. AT&T (the people who have the brick and mortar stores) and AT&T Premier might as well be considered completely separate companies. If you buy a line of service from Premier and take it in to a store, you won't get any help. If you buy a plan at a store, that plan cannot be transferred to Premier, and in fact
neither can your phone number.
My wife and I were "regular" AT&T for quite some years. We were AT&T before they were Cingular and stuck with them through the Cingular transaction and back to AT&T, went analog-to-GSM with them, the whole nine yards. Two years ago, I ordered a Premier phone for her and asked for her AT&T number (which was currently out of any contract obligations) to be ported to her net AT&T line.
The Premier rep recommended that we buy a line of service with Verizon for a month, port the number over to that, then on day 25 Premier could execute a number transfer to their division and we could go back to the Verizon store and return the phone under their then-existing 30 day "buyer's remorse" program. That was the ONLY way an AT&T Regular number could be transferred to AT&T Premier - through a wholly-separate phone company. Obviously, first that was more of a hassle than the phone number was worth, and second it was horribly unfair to Verizon even though we probably would have picked a refurbished dumbphone to keep their costs to a minimum.
My company offers two discounts.
1. If you go to an AT&T brick-and-mortar store with a paystub and an ID, you get 10% off certain things (services, some accessories, etc).
2. If you go to the Premier website, you get access to a separate and distinct selection of plans.
The two paths are completely separate. Choose wisely.