I initially acquired this Gullwing belt buckle as a flat brass piece with no back. I think it might've been some prototype and I have anecdotal evidence of at lease one other person having one (sans backing) that came directly from Gullwing. I have also seen one on eBay that did have a back although there's no way to know if it was added later. I picked up some backing hardware and tried to solder it on but that didn't work - so I had a welder friend weld the backing hardware on. That seems to have done the trick, so mine is now a functional belt buckle. Assuming this was made in the late 70s or early 80s.
Check the "belt buckle" for more vintage skateboarding belt buckles!