In ancient times with no light pollution they could probably see and track meteorites falling. And it could have been easier to access to get those metals than mining.

They go completely dark at a very high altitude. I feel like a bright sunny day would give you a better chance of seeing a falling rock, at least once it gets closer to the ground

Perhaps sometimes they saw it hit and went to find it? But the night is long and people should be indoors asleep near the fire and meteorites fall all around the clock anyway?

So perhaps they mostly just picked weird rocks up off the ground, as the Inuit did? When you spend time outside with the herds you probably notice unusual wrongs.