"Flat Feet" or Bad Feet in the military?

I am planning on joining the marines through NROTC (going into senior year in high school), however I sometimes have problems with my feet and ankles. If there's anyone out there that has this problem and is in the military, I'd really appreciate your help. A couple questions are:

Will I get rejected if I bring up this "condition"?
Can I just not bring up the issue, tough it out, and get through okay?
What would be the consequences if I didn't bring up the issue, and then had to drop out because I couldn't complete the training (dishonorable discharge etc.)?
(This one's a bit strange, but...) What are the boots you train in like?
If they don't automatically DQ you for having bad feet, would be at all allowed to get those shoe inserts (right now I'm using the ones you buy at the store for like $9... I think they're called "Superfeet".)

Thanks for any answers you can give.
Sorry, I'm sure this post sounds pretty lame for someone who is planning on joining the marines, and I'm sure some of the questions sound stupid as hell, but I just want to find out what the situation is for me.

A good friend of mine with the flattest feet I have ever seen was in the Military for 20 years. I asked him how that was possible and he just said that during the training that when they had to do the duck walk (something that people with flat feet can not do) that he stayed in the middle and just hung on to another guys shirt to keep stable and nobody ever noticed or said anything to him. That was over 20 years ago..so I don't know if they check into more extensively or not these days.