Track installation

I found a great deal on set of insulated garage doors.   I am having an issue with installing the tracks. When I line the track up to the garage frame the top gap is wider than the bottom. The top of the track is riveted together (see attached pic).  I believe I need to pop the rivets and move the track closer one notch.  If I'm correct,  what kind of bolt can I use so that the wheels do not catch the bolt head?   Thanks in advance.