Satch, if you are referring to Ramp weight, there is no true reference on the aircraft. The Block 60's do 'guess' at an Over 'G' event in air from the configuration loaded and the 'G' on aircraft - but those are not true and they can be fooled by switchology. None of these are the true weight of the aircraft as that is not loaded into the computer from the QA guys/gals who weigh the aircraft. The pilots use software to assist in their 'guess' but they can be off due to aircraft weights and configuration weight changes their software doesn't track.
The F-35 does need an input off 'true' weight and CG for its software.