I don't know the weight difference but here is the visual.
AF=Heavy
AH=Light
I'm sure there are some exceptions to the rule for date code to barrel profile but those date codes to profile for the most part are accurate.
Any member here with a AH 10" upper willing to provide measurements? Does the barrel taper down before the gas block or is that an optical illusion? Maybe place a 6" steel ruler there to show better?
Still looking for a photo of an AH dated/light profile 14.5" under the quad rail if any members here have one! Please....
TC