I have answered this in the other thread itself but i'll do it again
In the 600+ chapters in Naruto manga "SAKURA HAS NOT USED GENJUTSU AS AN OFFENSIVE JUTSU"
She has been shown to disperse it easily when cast by a non-sharingan jonin level ninja
Then your pic showing sakura identifying wood release from Yamato is not a proof for Sakura's ability to identify the 1'st hokage's juts's hand seal
consider this "if suddenly a tree or any other wooden things come out of the ground when the jutsu user did some hand sign" ....you dont need to see the hand sign to see its wood release,.... you can tell its wood release just by seeing the thing thats coming out of the ground its that simple
Being the Hokage and all Hishirama is known by all to be the only wood release user so you dont have to be a rocket scientist to find out its wood release(which anyone can do by seeing the tree coming out of the ground) and 1st Hokage's jutsu (common sense that him being the only Wood release user b4 yamato)
How are you saying Sakura will learn "Bringer of Darkness" ....from some scrolls she sees laying around ...

m being the 1'st jutsu i think it'll kept more secret and out of reach of anyone other than Hokages
or
do you think "Bringer of darkness" will be taught like this "hashirama -> his son/daughter -> tsunade -> Sakure"
This implies tsunade knows it already but that contradicts the fact she didn't use it against madara
Either way there is not enough proof she will learn it yet