This character was disabled in a patch due to memory management issues.
NCR recruits are a pair of new soldiers who were found at the obstacle course at Camp McCarran in Fallout: New Vegas, under the watch of the Ranger drill sergeant. However, they were disabled when the DLC patches were released, to free up memory.
They can be reenabled on PC with two commands: prid 0fe1e9 (0fe1cd for the other) and enable.