I guess you can say that. As you know, performance varies depending on the sails. Reported sail area is based on actual sail area. While nothing is 100%, builders tend to report SA based on their standard sails. Some will report using a Genoa to improve the performance number. Because you can always change sails, this is not necessarily the better number to use to compare boats. Using the rig measurement is better for that.
Also, keep in mind the other half of the equation, displacement, is almost always “light” which is with permanent equipment installed but tanks empty and without previsions, crew, etc. To my way of thinking reported displacement should be to the designed waterline but that is not always the case.