Yes. It took a bit of teeth pulling, but Niantic finally came out and said that doing your five PvP battles during the day of Community Day–I’m suspicious it means the HOURS of your local Community day–will guarantee them. Niantic said so in response to a trainer on Twitter asking.
I’ve seen convoluted responses posted on the web from Niantic support.
The left hand does not know what the right hand is doing so I would take it with a grain of salt. Different respondents will give you different answers so who knows what to believe.
I’d rather have the stones ready to go before the day in case it’s all rubbish.
I think it’s great. Now that my son knows he needs stones for next CD, he wants to fight me again.