Who knows this coin

I have this coins, I looks like the 1959 Poland PR 62.

But it is larger, is about 15 grams and has no reeded edge and no Essia on the left side.

I found a trial strike with that design N#161948 

It looks like for 1959 they used a different design. Are you sure yours is 1959? Could we see the obverse?

He was referring to this Pattern in his post: N#103708 KM# Pr62.

 I have no evidence, but if there are so many missing features (proba, edge) and the size and weight are different, the logical conclusion would be that it is a later reproduction of this „pattern“ coin.