My understanding is that it does not include partial enclosure, because each one is different. Veneers are also different: they range from boxes of tiles or stones all the way to layouts that are attached to a matrix base.
BrickWood’s instructions presume that you are using a local stone or tile supplier and are able to consult with them on your chosen material and application. The only advice I’d be able to offer about ordering online is to order more than you think you will need—factor in the 10% allowance that BWO includes in all its material lists, figure out roughly how many square feet your enclosure face will add, and go from there.
Sorry I can’t offer you a better answer with this one; but one additional thought is that you can ask how the veneer is packaged (how many sq feet per carton) and what your vendor’s return policy is.