✅ SOLVED Odd gold screw and nut design?

[beau7johnson]

Looks as if the nut itself had a screw seal outer profile. My guess would be for water or air proofing or space age nails haha. Any and all inquiries, thoughts and hypothesis are welcomed! Thanks, Beau Johnson
- dreamerView attachment 1582333

 

[reale bill]

need a clearer picture and a size comparison.