Ages and ages ago I saw in a theater (could have been TV) NOTD that wasn't matted properly. I could clearly see a guy riding a stationary bike below the Demon. The bike was powering the Demon's motion. I wonder if that was in your open matte?Used to own a 1.33 open matte 16mm print of CURSE OF THE DEMON. Some shots here and there looked OK but the bulk of the print had way way too much headroom.
Looking forward to the 1.85 Blu-ray. At least here's hoping it is.