Hmm not sure. I'll see if I can find anything like your talking about.
The steamvr/openvr APIs natively support Rift. If you're developing on Vive, you should be using those anyway so this may be a bug?
Ok. I have redownloaded and retried running the game, and it seems to work just fine now (SteamVR opens up and the controllers I see in game are the official Oculus ones). Great game btw! I have a small reccomendation, I do not know if it would be hard, but it would be really nice if when you hold a shotgun, you could grab the barrel/forehand of the shotgun so it locks your in game hands onto the shotgun like you would hold it in real life. This would definitely add to the presence feeling in your VR game :) This would also work great on any other dual handed gun you have in the game