1998 Chevy Corvette digital #'s for the radio theft deterre

I recently bought my 98 Corvette.
The previous owner didn't have the 3 or 4 digital #'s for the radio theft-deterrent feature.
According to the manual if the red light next to the volume control is blinking the radio is armed with the theft feature. I also read that if the battery is disconnected while the radio is armed it will no longer work unless you can punch in the correct code.
Since no one knows what the code is what do I do.
How do I reprogram the radio so it is unlocked?
Thanks