I think the question is a fair one but it is bound too much by the label.
Would you allow the mithral material bonus for studded leather. The actual leather in the world could be something worthy of the gold increase for the material and difficulty in acquisition - it need not be simply mithral studs vs metal ones.
Ideas:
Perhaps it has mithral studs and woven spider silk instead of leather.
Perhaps the leather is treated in special moonlight ceremonies that give it special properties.
Perhaps the studs aren't actually mithral at all but some other substance that shares the mithral material bonus.
Perhaps the studs are fused volcanic shards on a sharkskin base topped with chalots and overshies, garnished with truffle pate, brandy, a fried egg on top and spam.
Sigurd