Mercy Championship Series Skin?

So with all the league skins coming back, I noticed in my unowned filtered list that the championship skins are locked and not in the league shop. I don't think there were any streams where it was listed as a drop, so is this the only league considered skin that isn't available to purchase? Besides certain exceptions with some skins, I'm pretty sure that's one of the only ones that aren't obtainable during the sale.