Radar,
Your sig says you have a 99 truck, if so you would be better off posting in the correct years forum, I know the gauges from a 2003 wouldn't fit in a first gen without major modifications but I don't know about a 99. I do know that places like Summit sell new gauge backing plates in white for some vehicles and you could see if they are available for a 99.
Also there are places that rebuild gauges(maybe look in some street rod magazines) that could possibly do this for you.
Hope this helps,
Caleb