The top case back is correct for the regular Bentley motors, 3,6,9 layout with the date at 4o'clock
The bottom case back is the one used for the Bentley 6.75. This has the 3,6,9 layout also, but the day and date are at 12.
The other Bentley (with smooth bezel) has a picture of the Bentley Bontinental R on the back and has a brushed finished case
The Breitling Bentley GT (44mm 12,9,6) has engraved writing on the case back
The Breitling Bentley GT (44M 12,9,6) is a brushed case with a picture of a car on the case back also.