Not necessarily from cut and paste. The guy credited with enhancing the image could have gone in with the sharpening tool and caused the same artifacts.
I say it’s fake due to bad perspective and incorrect light source, myself.
Follow the steps in 11, playing around with it more.. if you also drop the saturation down to -100, you can actually see a square edge around the object that is the border of the cut and paste.. at that, the tip of the ‘saucer’ was actually cut off. With zoom at 400%, Hue at -150 and Saturation at -100, it looks like a postage stamp stuck in the sky.