I'm only guessing, but you item may be post Civil War. There were 100's of fraternal organizations in the latter part of the 19th century.
U. L. could be "Union League". The was a Union League of Alabama during Reconstruction. This item could be from a local chapter.
Can you be more specific about the location of the find?
Are you sure it is a buckle? It looks more like a pin to me.
DCMatt