Here’s the puzzle: The giant impact hypothesis predicts that the moon should be made of about 70% to 90% material from the impactor, so its isotope ratios should be different from Earth’s. But ever since researchers got hold of Apollo moon rocks for analysis, they have failed to find any significant difference in isotope ratios on Earth and the moon. Studies of the isotopes of oxygen, titanium, calcium, silicon, and tungsten have all drawn a blank.

This discrepancy has troubled planetary scientists so much that in recent years they have put forward a number of alternative scenarios to explain the moon’s origins. One hypothesis suggests that there could have been much greater mixing between Earth and the debris disk as it coalesced after the impact, or if Earth was hit head-on by a similarly sized impactor, their remains could have mixed completely. Another possibility is that a fast-spinning Earth could have been hit by a much smaller impactor, which would have provided little material for the moon. Yet it has been hard to show how you could get from one of those events to the Earth-moon system we have today.

I think a few surface rocks do not sufficient data make. What we need is a couple meters of drill core, imo.

Is anyone currently planning on drilling the moon?

The earth and moon have mixed remains theory makes the most sense to me.