I'm not sure what you are looking at to see mold?Is that mold I see?? Have you checked the straightness of both the shafts and butt??
That much mold, if it is indeed mold, means a lot of moisture got in there. I'd be surprised if it's straight. I hope it is for your sake and best of luck w the sale!!
This cue shows zero signs of mold in any of my pictures.
I believe you may be misguided by the phenolic which is an early form of building material used.
It has white/gray colored linen in it unlike the phenolic used today which has black linen in it and a more uniform overall color of black.
About the only thing I would do to this cue is MAYBE install a tip on the tipless shaft. That is it....period, end of story.