It's not that simple.  "Buy the rumour, sell the news."  Also, ASIC miners may choose this time to unload their bags once they realise for sure that mining is over on Dero.  So there might be increased supply.  At the same time lots of Dero supporters will stop being on the markets where they have been swapping other coins they have been mining for Dero, and turn their attention back to mining Dero, so there might be reduced demand on the exchange.  So do not be surprised if there is a price drop, even a significant one.

At the same time, it could go the other way.  Lots of people may be waiting on the sidelines to buy in once they have seen the Atlantis proof of the pudding.  Times like these are times of uncertainty for markets, not certainty.  I am not making predictions, just urging caution.