I would shoot, repeat, repeat and repeat before I started filing. It will loosen with time.
I would be wiling to bet that its the detent, not the stop. This should be tight when new and works it's way out over time every time you shoot, and take the pistol apart. I've never had a new 1911 that the slide stop just popped out without effort. This is usually the time when "most" people put an "idiot scratch" on it. Time and shooting/cleaning takes care of it. I guess I could have just said take apart, put together over and over but shooting is much more fun.How will shooting reduce the height of the slide stop when the inside top area is not touched when the gun is shot? Taking a tiny bit off the inside top of the slide stop will solve the problem, and will not affect operation of the slide stop.