Dang how did this thread bypass me? I assumed it was old because it was FFVIII and it had 4 pages. On the discussion at hand I think it could be possibly three things.

1. Seifer and Squall were self taught (I think this is probably the most unlikely, because if you're in charge of a military, probably the one of the worst things you can do is allow the students to teach themselves)

2. Seifer and Squall were taught by an instructor who used a gunblade before. He might have not been a specialist, but he knew enough to teach them how to use it and they decided to stick with it.

3. The same as number 2 but the instructor was a specialist, but he was just never a member of SeeD.