My dad hasn't split firewood in about 25 years, but he was still reluctant to give me the old axe. "That axe has been in our family for probably a hundred years," he said. "It was my great grandfather's. He gave it to my grandfather, who gave it to my father, who gave it to me. That ol' axe has split a lot of wood in its life." It looked pretty good for being used to heat several generations of homes through more than 100 winters. When I mentioned this to him, he said, "Well, we've taken pretty good care of it over the years...'course, it's had some repairs along the way. The handle has been replaced five or six times, and that's the third head that's been on it."
And so it goes with our beloved Corvettes. We can "restore a car back to original," but in truth, we're replacing the axe head and handle to one degree or another, especially when using reproduction parts. There's big a difference between buying repro (a new handle or head), and restoring the original stuff (a fresh coat of varnish for the handle, stripping the rust, and putting a fresh edge on the head). Given our druthers, we'll take restored parts originally built to GM specs over knock-off pieces almost every time.
We'd say that aside from brakes, there's nothing more important to your Corvette than the instrumentation. Gauges are there to keep track of all the things that keep your engine alive (rpm, oil pressure, and water temperature), as well as the things that keep you from walking (volts/amps and fuel level).
These gauges look like they've...
These gauges look like they've spent time under water...and they may well have: AutoInstruments did dozens of clusters from cars flooded by Hurricane Katrina salt water.
Gauges have two main components to them: the visual parts, and the mechanical ones. Visuals are the gauge faces themselves, the numbers, the pointers, and the bezels. Aesthetically, they fade, rust, and generally look dingy. Mechanically, components fail; pointers fall off, lubrication dries up, springs and other internal parts break, and sometimes things burn up. The only proper way to restore gauges is to take them apart until they're the same pile of parts Chevy's original supplier started with, and then restore them.
AutoInstruments in Martinsville, Virginia, has done exactly that for more than a decade. The company has developed specific processes for stripping, repairing, refinishing, and assembling Corvette gauges; refinishing the instrument-panel housings; and replating all the plastic chrome interior and exterior pieces. In most instances, AutoInstruments uses the same methods that Chevrolet's original suppliers used.
When your instruments come back, they'll be restored to OE specs and should be good for another 40 years. Because like the hickory handle and high-carbon steel head on that old axe, they just don't make 'em like they used to.

The process starts with stripping...

The process starts with stripping the instrument cluster down to its base components.

A lot of odometer mechanisms...

A lot of odometer mechanisms and parts interchange across numerous GM platforms, but Corvette instrumentation is unique.

Even the gauges are disassembled...

Even the gauges are disassembled to their individual pieces, just as the OE supplier would have started with. Here, a special tool is being used to pull the needle off the gauge.

The instrument's gauge cup...

The instrument's gauge cup is typically riveted to the housing. A Dremel tool cuts the heads off to get inside the gauge. When it's put back together, new rivets will be peened over as original.

This is part of the speedometer;...

This is part of the speedometer; note the crack. New ones aren't available, so AutoInstruments has a large supply of donors.

This is another part of the...

This is another part of the speedometer mechanism. The magnetic head of the part in the previous caption sits inside this bell and spins it. The tiny wound spring returns the needle to "0 MPH." The broken piece in the previous picture, or a broken spring here, will cause an erratic or non-moving speedometer.