It's my understanding that Marmot makes some different products for different retailers. Even though this may not be listed on the Marmot website, it doesn't mean it's not a genuine Marmot bag. You could always contact Marmot and ask them about it. This is their info: Customer Service: (888) 357-3262, Monday - Friday from 7:30am to 5:00pm (PST).
I own this bag and got it for a good price when Sierra Trading Post had a 35% off sale. It was a great purchase!