I was playing an 08' American Standard Fender Jazz the other day at a music store and noticed they had filed the fret ends. Probably to smooth the winter sprouting. But what I noticed was there seemed to be an inner metal bar or wire that was different than the outer fret metal. The inner metal was sort of brass in color. It had a very defined squared off shape to it (actually more rectangular) from this smooth filed end view. I thought frets were a consistant solid wire? Is this normal or a cheapy wire? Looking at a bunch of fret wire suppliers web sites I've yet to find anything like it.