What is the center piece where the T-tops join called. The piece I am talking about is metal and fits in the middle of the roof of the car. I also where can I found that piece. I think I am going to replace this piece because it has rust on it.

 

You can check my sig for a part #
Your best bet may be going new.
The problem with used that I've found is, even if you find a rust free one, normally, some dumb-ss has beaten you to it and didn't know about the 4 screws under the w'strip. Thus, prying on it and bending it all to hell.

 

I just got one from third gen resource used for 45 bucks that was in perfect condition. They are in NC so more of their t-bars are rust-free. I'd check with them
www.thirdgenresource.com