Boba's armour was Mandalorian in the TESB novel, though the name itself didn't appear till tie-in material. It wasn't so clear if he was.
EU sometimes portrayed him as Mandalorian (then, when he turned out to be a clone, Jango as Mandalorian) but Lucas saw the EU as a separate thing - to be drawn on occasionally when convenient, but otherwise ignored.A battered and tarnished chrome-colored droid named IG-88 was also with the group, standing next to the notorious Boba Fett. A human bounty hunter, Fett was known for his extremely ruthless methods. He was dressed in a weapon-covered, armored spacesuit, the kind worn by a group of evil warriors defeated by the Jedi Knights during the Clone Wars. A few braided scalps completed his unsavory image. The very sight of Boba Fett sent a shudder of revulsion through the admiral.
Thus, in an early TCW episode (Season 2?) a Mandalorian says:
"Jango Fett was a common bounty hunter. How he acquired that armour is beyond me."