Well, generally, you'd want the WMDs where you could get to them - y'know.... just in case. And, we have Lunar Orbiters that would likely find them -so, they're probably not on the far side of the moon.
Probably not on the dark side, either.
Elsewhere in the solar system is problematic also... It would cost *billions* getting them up there, then... when you need them, they're months or years away, which doesn't make much sense... And, we'd detect the rocket launches placing them up there in the first place, so... yeah, we'd know.