I don't have the product so I can't open it and check but since it says it is consisted of make up on psd layers and also states that it is a merchant resource, I would assume that you are correct that it would be transparent background make up that you could apply over any texture you want :D

As I said I don't have the files so this is probably the best answer I can give you :(

Sorry that you haven't gotten an answer from the product creators, perhaps they have not been online.  

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