Radio Delete Cover

I have noticed that on a few 355s that there is a leather cover where the factory radio normally lives. The best way for me to describe it is a similar appearance to a radio delete plate that the American muscle cars wear. Of coarse since we are talking Ferrari, it is leather. I am new to the 355s so if it is an obvious answer, please go easy on me.

I am trying to learn as much about the 355 as possible so when I purchase one, I don't go in naked.

 

So does that mean the cars are born without radios, or are they deleted later on?

 

Thanks-
I guess if it came with a radio as standard equipment it would be on the window sticker.