It's listed as on a ranger sniper that shows up in the cell where you fight oliver when playing through legion. I just ran on old save I had through there, and didn't see the sniper where the geck shows him spawning. This is the part of the geck I svck at, checking inside cells and stuff, so maybe someone who knows what the hell they're doing could look into this.
-Gunny out
I'll check the geck but I'm not sure that I will find anything. I usually just use the geck to make mods that are pretty simple, like weapon and armor mods. If anyone out there is a geck expert, maybe they could look into this.
Edit: I think I just found the sniper in the geck, the entire cell he is in is not finshed, and the sniper himself is considered moveable static rather than an NPC. If I am correct, I think all of this means that you will not be able to find the sniper in game because the cell might be completely inaccessable. The cell appears to be under the area where you confront General Oliver.