Clicker, if a barrel scores a bullet perhaps a bullet also wears the barrel?
In fair condition due to the level of wear on the black finish
I would have thought that all weapons will have been proved before issue ergo it must have been fired at some time.
According to this site
Glock Serial Numbers a G19 FZR - G-19 - Unknown - 3rd Gen. - LCI Extractor would have been made around 2004. The site does not list FZF serials.