I don#T get it...... You have the texture (e.g. on a prim) and need the UUID? Or do you need the UUID from Content of the Prim? Or do you want to touch a prim to get the UUID of one face?
A texture's UUID allows you to use a texture you don't have in your inventory. You put the UUID finder script in an object and the script gives you the UUIDs of the textures used