My first impression was that it was modern (made within the last 5-10 years I would suggest) - from the way the diamantes are glued in, not particularly carefully and the dark tone of the diamantes) and I think the photos of the back confirm this - it shows lots of mould lines, has not been polished or smoothed out and is darker in the creases left by moulding suggesting a colouring has been added after casting to give it an 'antiqued' look. The bar stud fastening I have only seen on belts from the 70s/80s onwards and is very common on cheaper modern belts today. I don't think it was intended to deceive - just that seperated from the belt itself, which I think would have been a contrasting modern style, it looks older than it really is. The curved/domed shape also lends itself to a modern dating I believe, I can recall seeing this on belts alot some years back.