Will this bezel fit my existing gauges?

If your gauges are standard 2-inch round instruments, they'll drop right into these holes. Verify gauge diameter before ordering—most vintage C10 setups use 2-inch gauges with no issues.

Do I need to prep or paint this before installing?

It comes ready to install as-is. The black plastic finish matches factory stock. If you're restoring to a different color or want a custom look, basic sanding and spray finish work fine on plastic.

What's the best way to secure it to the dash?

Mounting method not specified—test-fit first to confirm how your dash fastens (clips, screws, adhesive tabs). Once you see how the original was mounted, you'll know exactly how to secure this replacement.