Meteorites tell us that there are some hard bits in the asteroids--indeed some theories hold that a planetoid, big enough to have the heat and pressure to make rocks, broke up to make the asteroid belt--and all that frail-looking stuff suggests that a lot of the meteor gets splattered away high up in the atmosphere.
The meteor trail in the air is mostly glow from heated oxygen and nitrogen, but I'd expect some amount of light from the frying meteor as well. If (That's a big if. As it says at the link, usually you don't have a spectrometer pointed at the meteor trail.) you could compare the spectrum at the start and at the end, and subtract off the atmospheric contribution, you might be able to tell the difference between the composition of the soft cruft and the harder bits.