Looks to me like it's been painted. I don't think that white is patina.
Surf is trying to help you ascertain a value but you're not giving him enough to go on. I highly doubt he's interested in buying it. We need more, better pics.
1. Lay it out flat on the floor, and take a pic of the whole thing. Nothing else should be in the pic. Do this again to all sides (should be 4).
2. Take a close-up shot of the manufacturer's plate.
3. Take some pics of the lamp itself, from all sides, just as you did for the whole thing. Should be 4 pics, one of each end and each side of the lamp. The entire head of the lamp (but nothing else) should be in each picture.
4. Take some pics of the mount, shaft, and rotator. Maybe 3 pics total.
5. You should definitely test it before you sell it, and maybe take a pic as proof (you could substitute the proof for one of the #1 pics). The owner's word on functionality means nothing to potential buyers. They will want to see it for themselves.
Thanks! Hopefully we can figure out more about it and find a value for you.
Upload these to your original post. If you do happen to figure out a value, any potential online buyer will want all these pics to be uploaded to the listing.