If they are from Kalamata in southern Greece, they are Kalamata, otherwise they are Kalamon. Of course not everyone will agree about this, as “Kalamata” makes it easier to sell.
They aren’t hard to find now, because I too hunted for them ☺️
I agree that Kalamata whole are very tasty. But please don’t eat them directly from the jar or even cold. Warm them in a little olive oil. In an oven or however you can. That really makes them juicy and releases the flavour.