I put the standard Warren Tactical rear sight and fiber optic front on my Gen 4 G19 and am very happy with them. I shoot IDPA and these sights have definitely helped my accuracy a ton. I dont carry my G19 so it's pretty much just a range/competition gun but I can tell you that based on...
I'm pretty sure I saw one yesterday (od/stainless) at Midwest Gun Exchange in Mishawaka, IN. I'm pretty sure it was used but appeared to be in real good shape. Good luck.
Edit: I have a 3.8 compact in .40 S&W and I like it alot. You can't go wrong with the XDm pistols.