I went to start paperwork on a new 6" 629 today to replace my old one. Someone here got a gun recently with a badly machined bore so that was one thing I checked. Other than faint scratches that ran strait front to back the bore was clean as a whistle, no rifling at all. The shop owner was impressed I caught it so fast. I should get credit on the 10 day wait but it's all take and no give.
So check your purchases carefully, make sure there's a trigger and such.