I've owned rifles from Bushmaster, RR, Armalite, Noveske, LMT, KAC, Larue, Colt, LWRC, BCM, and have assembled using plenty of other companies as well.. My opinion is that you never know whether or not you're going a part free of all imperfections. Some companies concentrate more on the finish while others care more about performance.
I've also seen dings and scratches occur during transport, at the dealers, being handled by customers, etc.. Many moons ago I used to be a little anal about these sorts of things but, if you plan on using it, I say that it isn't that bad so just rock on.
I do get the arguement from those saying they want to be the ones that put those scratches on there from use so, it really just boils down to how much it bothers you and whether or not you want to pursue a resolution.