Gunblade specialization

[Future Esthar]

My point is that he couldn´t have learned it at the Garden.

Cid´s actions seems to imply being a specialist on gunblade it´s not a criteria to become a Seed and therefore he can´t force one to become it.

Balamb Garden specializes on Para-magic,the general battle system and general military considerations.
It don´t teach you how to use a nunchaku or a rifle or a whip,etc...
At least there isn´t evidence on it.
BG studies each students inner ability and equip them acordingly.But they don´t get training on each of those.

Instructors at Garden have to be SeeD right? That is a bit of a plot hole.

Good point.
Who were the first instructors?
Esthar scientists?
Cid himself?
Maybe the first instructors were just to read books from Esthar to learn things.
Or maybe the Shumi´s have already this knowledge.