1. "built the same project and sent it to CV1 and I did not encounter this error"
2. "the DllNotFoundException OculusPlugin is not found when sent to the CV1"
FYI: I ended up just re-writing my player controller, but in the interest of why this happened, let me explain:
I had a project with an OVRPlayerController. If I build it, it will run perfect on CV1, e.g. the xbxo one controller will control the OVRPlayerController as it would in the Editor. I needed to port the project to Vive, so I imported the SteamVR Plugin for Unity, applied SteamVR_Camera.cs to OVRPlayerController CenterEyeAnchor, set the Virtual Reality SDK to OpenVR (removed Oculus) - I assumed this would fail for the reason I explain below, but I was curious.
Now, if I run the scene, everything works fine in the Editor, e.g. xbox one controller will control the OVRPlayerController even though it's being rendered to the Vive!. If I build the scene and launch the .exe to run on Vive, I catch the .dll error I mentioned above, which is weird because it worked perfectly in the Editor. The reason, I assume, is because the OVRPlayerController is wrapped in a bunch of Oculus callbacks that fail when the .exe initializes and doesn't detect am Oculus device. I was curious if I could bypass that by converting the camera to a SteamVR camera. This worked in the Editor, just not when I build the .exe.