Why would you artificially relic a guitar thats already vintage? Now I am confused. Or was it a restore or fix job?
I'm talking about a vintage Martin that needed extensive repair and/or restoration work, and the luthier wanted to make the repair blend in with the rest of the guitar. At the lowest level, it might be deglossing or checking a small area of overspray or lacquer touchup.
This "relicing" can be as extensive as retopping a guitar--in which case the wood itself might be "suntanned" so that it has that golden color of an old Martin. Sometimes a new neck needs to be made, and there might be an attempt to subtly replicate some playing wear. One particular luthier is so good that he replaced the a damaged side on a 1930 Martin OM-28 (a $70 K guitar in mint condition) and some very prominent experts couldn't figure out which side was real and which was the replacement.
Most acoustics have rosewood or ebony fretboards so there's really no point in relicing them.
FWIW, I would think that the real expert relicers, guys like Jonathan Wilson, treat even solid body guitars rather gently. I would bet they use sandpaper and not an electric sander, and the "abuse" (say, dropping or denting the body) is only a very small part of their craft.
It's funny, in the acoustic world, many of the greatest crimes have been committed in the service of covering up relicing. The Martin factory would overspray guitar routinely, and put giant, hideous ugly pickguards to cover play wear, which is a huge hit on value now. One of those pickguards is on an insanely valuable pre-war D-45 and a friend of mine joked "Wanna see a $30,000 pickguard?"
best
Allen