Rare? Playboy Sunglasses model 4561 31

I have had these glasses for some time. My partner's grandparents owned an opticians in central London many moons ago and kept a few of the glasses when they closed for retirement. They have since passed away.
I was lucky enough to be given these glasses which I liked the most at the time.
Never worn them, apart from when I first looked in the mirror as I first tried them on.
I have seen one pairr online that were sold in USA many years ago so I belive they are ultra rare?
I also found the same model was worn by Will I Am from the Black Eyed Peas band, who is famous for wearing the most bizzar glasses.