As a NG, when I leave for 25B training, will I receive BAH based off the zip code of my dependents?

Yes. An MDAY in the Guard on Active Duty for Training (ADT) order receives BAH based on HOR or dependents HOR if different. Your AGR will need a current DA 5960 from you to process those orders for pay before you start.
Otherwise you will have a BAH problem.

It usually works like that. Make sure your paperwork says the city they will be at so you get the correct BAH.

Yes, I'm NG at AIT, and I'm receiving BAH based on my home zip code. Make sure to brind different types of documentation stating that you are married, pay rent, have dependent (if that's your case). Sometimes they reject some documents. That way you will have a backup plan.

Also your first pay may take upto 40 days to be deposited in your account, so make sure to have some money saved.

Remember, they are humans, and make mistakes. During BCT I received BAH type 2, which is like $250 a month (and that's wrong). Once you get your first paycheck, make sure you have regular BAH. FYI, I did get back pay for those months that they gave me incorrectly, but the struggle was real.

Good luck, and enjoy it.