Thanks for the pics, helps to see what we are talking about! I tried to scan my gauge face, came out a a little grainy, the face is above the glass a 1/4" or so, that may be the problem.
My gauges don't look that bad . . . Thought is to scan a good gauge face, photoshop the needle out, print and stick it on the blank plate. Not sure about paper? vinyl or adhesive backed label paper? I was gonna try a local print shop to see if they could make an emblem sticker for another project, they may have some ideas.
What year truck did you pull the voltmeter from? Square box? means 80s? guess i need to head out to the yard and go looking . . .
Roy