Unless they repealed Archimedes's law, a boat's displacement is equal to the boat's weight at some theoretical loading. (and that total displacment would include ballast). Since the designer usually gets to sellect the loading at which he calculates the displacement, the designer can chose to use a dead empty weight, or some partial loading or some maximum loading. Race boats are the exception to the designer chosing the loading at which displacement is calculated. Race rules define what can and what cannot be used in calculating the displacement. The Ranger 22 was an IOR mini-tonner and so had its displacement calculated as defined by the IOR rule of that era which would have included normal gear aboard.
If you can find one, a Ranger 23 is a far superior boat on all counts.