Dell Optiplex 755

I am considering getting an Optiplex 755. The main issue I run into is that I do not know which of the versions it will be (MT, DT, SFF, or USFF) until I actually receive the machine - just the way it is when I get them from the dealer I am buying from (used corporate machines, so rarely the USFF but it does happen). I am just curious if any of the designs are known to be able to use the Core 2 Duo E7400 CPU? I see the specs at Dell say the below CPUs work, what are the odds a E7400 would as well?

processor (speeD, cache, fsb) mt Dt sff usff
Intel® Core™ 2 Quad with Intel VT, Enhanced Intel SpeedStep Technology, Intel 64 and Execute Disable Bit
Intel Core 2 Quad Q6700 Processor (2.66GHz, 8MB L2 cache, 1066MHz FSB, VT) ✓ ✓ ✓ (no usff)
Intel Core 2 Quad Q6600 Processor (2.4GHz, 8MB L2 cache, 1066MHz FSB, VT) ✓ ✓ ✓ (no usff)
Intel® Core 2 Duo with Intel vPro Technology, Intel VT, Intel TXT, Enhanced Intel SpeedStep Technology, Intel 64 and Execute Disable Bit
Intel Core 2 Duo E6850 Processor (3.0GHz, 4MB L2 cache, 1333MHz FSB, vPro, VT) X-GSP X-GSP X-GSP X-GSP
Intel Core 2 Duo E6750 Processor (2.66GHz, 4MB L2 cache, 1333MHz FSB, vPro, VT) X-GSP X-GSP X-GSP X-GSP
Intel Core 2 Duo E6550 Processor (2.33GHz, 4MB L2 cache, 1333MHz FSB, vPro, VT) X-GSP X-GSP X-GSP X-GSP
Intel® Core 2 Duo with Enhanced Intel SpeedStep Technology, Intel 6.4 and Execute Disable Bit
Intel Core 2 Duo E4600 Processor (2.4GHz, 2MB L2 cache, 800MHz FSB) ✓ ✓ ✓ ✓
Intel Core 2 Duo E4500 Processor (2.2GHz, 2MB L2 cache, 800MHz FSB) ✓ ✓ ✓ ✓
Intel Core 2 Duo E4400 Processor (2.0GHz, 2MB L2 cache, 800MHz FSB) ✓ ✓ ✓ ✓
Intel Core 2 Duo E2180 Processor (2.0GHz, 1MB L2 cache, 800MHz FSB) ✓ ✓ ✓ ✓
Intel Core 2 Duo E2160 Processor (1.8GHz, 1MB L2 cache, 800MHz FSB) ✓ ✓ ✓ ✓
Intel Core 2 Duo E2140 Processor (1.6GHz, 1MB L2 cache, 800MHz FSB) ✓ ✓ ✓ ✓
Intel® Celeron with Execute Disable Bit
Intel Celeron 440 Processor (2.0GHz, 512K L2 cache, 800MHz FSB) ✓ ✓ ✓ ✓
Intel Celeron 430 Processor (2.0GHz, 512K L2 cache, 800MHz FSB) ✓ ✓ ✓ ✓