No, its none of that. The only software difference is the $20.00 server app. Same Mavericks. You can add the server app to any Mac anyway.
The Server has two 1TB 5400rpm drives. There are also added flex SATA cable, screws and labor for the install.
Otherwise the logic board, CPU, GPU etc etc is identical to the non-server equivalent.
Perhaps the price difference on having an SSD in the Server version is that they have to do a manual build on the drives.