Could Japan have hidden Kaga from treaty limits?

Could Japan retain Kaga for later carrier conversion if Amagi survived and Amagi and Akagi became carriers?

Only by hiding the work and disguising Kaga as something like a seaplane-support ship until a later rapid carrier conversion.

Japan might have moved the hull to an obscure fitting-out location and completed it slowly under another description. A seaplane-support ship would have been a plausible cover because hangars and aviation facilities could be explained before a flight deck appeared. The pre-satellite environment made physical concealment more feasible than it would be today. Even so, the plan would have depended on extensive treaty cheating and secrecy rather than a legitimate interpretation of the limits.