Not sure if it matters if it’s ready. Vekoma has announced repeatedly that Good Gravy would open first, they used cars from the train as part of their display at IAAPA back in November. Where they again announced it would open first. Something has the manufacturer convinced, it will be first, even with Kings Island opening for the season first.
I suspect Vekoma built a no earlier than date into the contract. Basically Soap Box Racers cannot open for media or guests before X date. The ride might be cycling, completely ready, and still not be allowed to open.