[s]Can anyone confirm if this location is correct? I've been scouring the area for an hour and I still can't find it. I've even been killing regular doomgazes, just in case they are a placeholder.[/s] Nevermind, found it on the east side of the road. The other site I was looking at was showing it on the west.
For roaming NPCs we can show only the starting spawn position. After the spawn they can go pretty far, depending on their patrol route. So in general it would be wise to scan the area around indicated point to find the NPC in question.