My radio died and I’m looking to replace it with an OEM radio on eBay. These radios have different serial numbers and I assume that I need to get one that matches mine.

My question is; would that serial number be identified anywhere other than the back of the radio?

You will never find a radio with your serial number. Your radio has it's own unique serial number.
You can find one with the same PART NUMBER but not serial.

The numbers are printed on the radio chassis.

So is it safe to say that a radio with the same part number will work in my vehicle, regardless of whether or not my Audio accessory options (amp, nav, cd, etc.,) ?

I’m sure I can purchase a new head unit with more features, but I want to try to keep it as OEM as possible.

I need to correct this radio difference.

There are two different radios if I remember correctly.(1998 to 1999MY and from 2000MY to 2003)
I just looked at all the X308s I have and the early cars do NOT have a NAV button but the later cars do.(no matter if equipped or not)

No idea what car you have so can't recommend a part number.

Makes sure you get the radio code for whatever unit you buy as the head unit contains that, not the car.

As I recall an easy way to tell the early & later radios apart is the position of the volume dial. One is much higher than the other so an easy visual difference to notice.

Oh, just thought of something else. There's a switch on the head unit to change from the standard to premium audio, it changes the outputs used. Just check it's in the same place as on your old head unit before you fit the new one.

First of all, thanks for all the suggestions!

Here’s the conclusion of the radio saga.

What I didn’t share with you in the original post (because I didn’t think it was relevant), was that I had bad front speakers.

They worked, but they were rattling.

I took the car to an Audio shop this morning to have the speakers replaced.

The tech said that in many cars, including Jaguar, if the speakers fail or short out, the radio will automatically power off as a protection.

I was thinking, BS but, when I went to go pick up the car, in fact, he had replaced the speakers and the radio was working! Go figure?

Yup that's the amp protecting itself.