Methinks it may be a fake. The big front looks like the tokens were set on top of a batch of concrete and there are few actually embedded. The tokens are all flat and too uniform and "clean" to be legit IMO.

I'm familiar with the large concrete at Spinetis and it is an obvious fake IMO. I actually owned it for a day until the obvious bogus fabrication became evident and I returned to to the dubious seller.

I have several of the dig concrete clusters and find them to be fun conversation pieces. I'm a buyer if anyone has any for sale.