Meridians

I have a description that was written mostly based on a company ROS. My task is to set the second and third corner monuments of this long description. Although it's based on the ROS it's rotated from state plane which is the ROS basis of Bearings to "GPS North". Whatever, "GPS North" is. I'm pretty sure a base was set on a particular control point onsite that's shown on the ROS. Projecting north if you set on it gets me within a few seconds of the rotation. But, there is no notation of who wrote this description. There are no monuments that I've found for the few common corners I'm interested in. But there is one piece of evidence to puzzle out the surveyor. That's the word Principle, as in Principle Meridian from the description. I think I know who did it from that.