As long as proper polishing techniques are used and not a buffing wheel, there will be no ill effects on engraving. The only time one would have to really worry about engraving with proper polishing is if pitting is present. But if you are just refinishing due to normal wear, no worries in the right hands.

It is not uncommon on many guns for the guard to wear out it's bluing first since it is in a area of high handling. Especially the guard tang.

B.Dudley