If the sights were not factory installed then it is more likely that the front sight would give that away rather than the rear. Unlike all the larger frames installing J adjustables does not require a milling cut for an elevation nut. Installing J adjustables is so simple that I did one with only files, a drill and a tap. It looked factory. The required high front is harder to make look right.

I'd like to see a picture looking straight at the muzzle.