M&M is a tour broker, not a vendor. They're selling the Temsco tour. If M&M says you get boots, that's what Temsco is doing. There are 1 or 2 other options for flightseeing in Skagway (contrary to popular belief here!) but they'll run you a few thousand instead of a few hundred, and are generally used for research and private charter jobs.
Book the Temsco tour directly. You'll have a blast!
Oh, and I agree that if you've got other priorities in Juneau it's worth it to see the same ice-field in Skagway.