pretty sure they're like the equivalent to fingernails? her first outfit in the yellow dress has them colored yellow but everything since has been black/gray, so I think they're either cosmetic or painted.
Amy and Lanolin colored with and without stockings, plus an alt for Lanolin with more traditional skin arms and no 'hooves' or whatever the fingertips are supposed to be
I'll actually make an exception for this one, I'm still working on it and adding more characters but i did share this one around because i really liked the WIP result.