I have a bunch of UV mappers, ranging from classic, free 'UV Mapper Classic', via the one built into ($$) 3DOC, to the ($$) 'Ultimate Unwrap3D', ($$) 'Lith Unwrap2017' and their clever kin. Truth be told, some easily match up to mapped textures, but many do not. I often resort to a 'binary search', trying to identify which part of a complex, broad-brushed, mapped-texture belongs where. As I say in reviews, 'Template much appreciated.'

This is not just for figuring where a ported model's features / accessories / ornamentation textures may be found, but setting up reflection and emission masks for a scene's mirrors and luminaires. Yes, yes, you can set up 'groups' within Poser, but gets very messy when trying to save-out to external library. Very rarely can you 're-map' just one mapped material of an object. And, process usually degrades 'portability'. Much neater to have simple B&W masks which 'plug & play'...