In season 2,episode 3 "partners",of "THE SHIELD" you will notice that in the scene shortly after Vic has been shot there is a close-up of Vic's.45. This is however a different model S&W4506 than the one we usually see him taking down scumbags with.You see Vic's "usual".45 wears the S&W protected,or "winged" if you will,Novak rear sights,not the fixed 3-dot sights that we see in this particular episode.The fact that these two rear sight sets are not readily interchangable among the 4506's means that these were two different weapons.