New Zealand Decimal Currency Medal

I was 6 half years old when they introduced decimal currency to New Zealand. I can remember the classes in school and the black and white television adds. A couple of days ago I was checking in a cupboard and discovered a medal dating back to then( but purchased in the last 10 years). I had forgotten I had it.

It was issued by the Royal Numismatic society of New Zealand The reverse shows the coins issued in july 1967 and they actually used actual dies and working models from The Royal Mint to produce that reverse ( the representations on the medal are life sized). The mintage numbers Silver( bright) 200, Bronze (bright) 500, Silver toned for presentation pieces(50) Bronze toned for presentation pieces (100) My example is a bronze bright. Medal is 63mm in diameter: