I can tell just from looking at the seat maps on Delta.com.
There are 8 different seat configurations for Delta 757s.
75A - 16/150 - Overhead TVs
75J - 20/162 - No IFE
75N - 22/160 - No IFE (former NW
5500 series, 4 doors)
75N - 22/162 - No IFE (former NW
5600 series, 3 doors and two overwing exits)
75E - 16/158 - In seat AVOD
75V - 22/156 - Overhead TVs
757 - 24/159 - Overhead TVs
75U - 24/159 - Overhead TVs (Same a 757 but with winglets)
75X - 26/158 - In seat AVOD