Fixing texture on Dash

[cp72ss]

Hello,
I am finishing a 72 SS Chevelle and was wondering if anyone has fixed an original dash. On my existing SS dash there are a couple of holes that were drilled for aftermarket switches. These holes are not big but my concern is if i try to fill and sand the dash I will smooth it out and no longer have the original texture of the dash.

Any suggestions on how to fix the plastic but yet still retain or create the texture pattern in the plastic?

Any help would be appreciated.
thanks