imei, maybe, but i doubt the wifi MAC address...
i, for one, have gotten a headache thinking about this... BB fine print on the in-store $200:
"Valid 9/19/14-10/16/14. Order online or in store varies by carrier. Valid on purchase of Samsung Galaxy Note 4 on AT&T, Sprint or Verizon. Taxes/surcharges due at time of purchase. Taxes applied to price of phone prior to the gift card credit. Not all phones are eligible for trade-in and trade-in value may vary. Excludes phones that are cracked, water-damaged or that lack power. Not available in all locations and some stores may have additional limitations. Not compatible with other trade-in offers. No rainchecks. See BestBuy.com/TradeIn for full details.
*Online pre-orders must choose "Store Pickup" to qualify for trade-in offer."
The particular sentence, "Taxes applied to price of phone prior to the gift card credit" makes it sound like the $200 gift card will be applied to the purchase of the phone. *sigh*