I think that I bought the 1% without CD covers. These are a few where I got "cover not found".

Jean Pierre Rampal FreeDB ID 0E100514 revision 5
Andreas Scholl 1E107F13 rev.7
Cafe Rembetika 0E100514 rev 5
Baldi Olier 50109814 rev 2

I didn't list those which had revision 0 (bought in a store) and those which had only wrong covers.

How is the FreeDB ID created? I found that I scanned a disk twice, the original and a copy for the car. They had different IDs, the copy had version 0 and the original a real number. Does the ID show it's a copy, or is there some code that could be meaningful?