The "bow" is the frame of the top that rests on the deck lid cover, I think you mean the forward part of the top that rests on the windshield frame - not sure what they call that.

I've seen some cars that the front of the top wont' stay up on it's own - I believe this to be a problem with the spring/linkage in the top frame. I'm 300 miles from home in a rental car - can't go out and look mine over to advise you till late next week.