Currently the F4F Family (including F-4F Early, F-4F, and F-4F KWS LV) all have an empty weight of 14,375kg. The F-4E in game currently have an empty weight of 14,205kg, 170kg lighter than the F variant. In theory the F variant should have a lighter body than the E variant since multiple systems including a fuel tank got removed. (As shown and modeled in game)
F-4E
F-4F (Rear most fuel tank removed)
But in game the F-4F family is 170kg heavier than the E variant.
Online sources listed the empty mass for Luftwaffe F-4F is around 13,800kg, which is about half a ton lighter than what we have in game.
Source 1
If anyone have any unclassified information about the empty mass please help.