You don't have to order an Old Town Canoe through Gander Mountain. There are other retailers. I would call ( not email ) Gander Mountain to find out why the shipping charges are so different. I understand that Old Town is in Eastern Maine (not far from me) and Perception is closer to MN but I can't reconcile that big a difference.
If the $400 shipping charge is to have an Old Town delivered to Gander Mountain I doubt they are selling many. If that was the charge to have one delivered to my front door, wrapped with a big red bow, I’d still never pay it.
You seem set on purchasing a new canoe. Depending on the price delta between different retailers and the driving distance to go inspect it and pick it up I might pay the $50. Tops.
I may be out of touch with the marketplace, but if I would expect a big box retailer to get me a poly canoe in their next semi-load for free.