I did the same thing as well, except my attack was more...premediated.
I had planned on getting that armour for awhile, so when the Veteran Rangers finally came, I waited for one of them to sleep at Camp Golf and then put a grenade into his pants with the help of a stealth boy. Another time, I pushed one of them off the tower at Camp Forlorn Hope and then killed him out of sight. (Also using a Stealth boy)
In both cases, the NCR turned hostile, but I didn't lose any reputation with them, and they all turned back to friendly/neutral after my Stealth Boy expired. Somehow, they were hostile when the Stealth Boy was active, but not when it was deactivated.
IMO, It's one of the nicest-looking armour in-game.