I've just been into ATS to see a mate of mine and he said, don't touch them. There's always a risk, also it's more a question of how and where they have been stored. All new tyres are stored flat in the factory.
He said if there very cheap and you want to stick on the motor for a bit of Greenlaning he then upto the buyer, but road use no way. He said your better buying some with a couple of thousand mile on them.
I'm going to leave alone.