Metallic spheres are one of the easiest things to create naturally. We used the principle in shot towers throughout history to make bullets. I'm just an armchair expert, but it doesn't surprise me in the least we'd see near-perfect metallic spheres from a meteor burning up in the atmosphere.

My understanding is that metallic spherules from iron meteorites would be expected to include nickel. The absence of nickel in iron containing spherules like these would usually indicate a non-natural source i.e. human technology. The speed and trajectory of the meteor which may be the source, however, indicates an interstellar origin.

I believe that initial analyses of these spherules has revealed an absence of nickel.

The spherules were recovered from areas in the expected debris zone; none were recovered from the surrounding, control zones.