ᐅ Wood battens have discolorations—are these acceptable?

Good morning,

I just received my wooden battens for the substructure of the rough decking. Unfortunately, they look somewhat “off.” I checked by feel, and they all seem dry. Now my question is: can I install them like this in the attic (cold attic), or should I sand them beforehand? Is this mold? Attached are a few photos.
Thanks!