In D&D 4e, there are superior "masterwork" versions of armour types, like "feyleather" for leather armour or "wyrmscale" for scale armour. They have a higher armour bonus, but a minimum enhancement bonus, and a price of "special".
How exactly do masterwork armours work? Does any leather armour of +4 or greater qualify to be feyleather for a free +1 armour bonus? Is all +6 plate armour essentially Godplate?