Originally Posted by mrcvs

Thank you. Now it is obvious that the front sight has been removed and relocated.

Also, in hindsight, it was obvious that this was not an original 4" barrel. The reason why is that the barrel markings are in the proper location for a longer barrel. Compare this to my revolver, which letters with a 4" barrel (although difficult to read due to previous refinish(es)). The markings of this revolver obviously differ from those of the original poster's revolver.