Additional AT&T rep who arrived as my Fiber Technician was installing internet?? Scam?

So I had fiber installed in my house yesterday, shortly after my technician arrived, a second supposed AT&T employee arrived to help me set up my account and explain the features of my internet.  At the end of the explanation he asked If I was interested in getting wireless phone services as well.  The deal offered seems to good to be true, and I don't know how to verify the legitimacy of the visit.  The technician didn't seem to be be bothered by this additional employee and they conversed a bit about what they were doing.  He offered me a 100$ 5GB flex plan which included two AT&T Next lines with a 10$ discount for autopay, and another 5$ employee discount lowering the final bill to something around 85$ a month.  In addition, I had the choice to receive an iPhone 8 or Samsung Galaxy S9 for free only having to pay for the sales tax of the device under the stipulation I stay with AT&T for 24 months.  Not only that but having phone service would lower the bill of my internet service to 70$/mo forever, negating the raise in rate after the initial 12 months.

The deal seems a little too sweet, and I didn't even plan for this rep to visit..   Is this legit?  I've read online that the door salesmen offers are not honored by AT&T whenever the first billing complications end up happening.