General Description: Do the data book values apply to all devices rated Commercial, Industrial, and Military.
Yes: The military grade part with the same speed grade as the commercial grade part is actually faster when both parts run at the same temperature.
Xilinx states that for any given temperature grade part, we guarantee that the device will perform according to the worst case delays indicated in the speeds file when operated at its upper temperature limit.
A higher temperature grade part (say a military grade part) will run up to the same speed at the the maximum military temperature limit that a lower temperature grade (say, commercial grade) part will operate, at its lower, maximum temperature limit. If a military grade part is operated at the commercial temperature limit, it would be faster than the commercial grade part at that temperature.
The Xilinx timing and simulation models are for:
Voltage: 5 volts -5% for commercial grade 5 volts -10% for industrial and military grade
Temperature: +85C junction temperature for commercial grade +100C junction temperature for industrial grade +125C case temperature for military grade
Output Loading: 50 pF
This has changed with the introduction of the XL parts -- the output loading is rated at 35 pF.