Actually: NO

On July 12th 2018 - 16::00 UTC upgraded miners will be able to begin signalling their upgrade status in the blocks they mine. Every 2016 blocks (roughly 3.5 days) the quantity of upgraded blocks is measured and once a sufficient percentage signal upgrade Phase 2 will become "locked in"; after this another 2016 blocks window period is allowed before Phase 2 becomes fully activated.

When Phase 2 activates the witnesses can start filling their witnessing acounts and when the threshhold for the amount is reached Phase 3 will activate, and THAT is the moment PoW-reward will change from 100 to 80.

See: https://github.com/Gulden/gulden-official/blob/master/technical_documentation/PoW2_activation.md