Can't Recolor Vampire Fangs

I think this is likely a silly issue that I'm just missing, but I'm trying to add a separate version of the Vampire fangs (just the 'classic' ones with the two canines) that have silver or gold caps over the fangs. I saved the swatch from the vampire teeth, but it's blank. Regular teeth swatches are totally fine - I saved the gold teeth one and the one with braces just to check, and those have a tiny section off to the right side for teeth. 

Do the vampire teeth just use the same textures from the base game?

If so, how do I go about making an additional swatch/recolor for my idea?

Thanks for any help!