I work with someone who used to be in production at Starbucks. I can't say for certain what they do today, but I have it on good authority that they do not "doctor" their beans.
EspressoSue - the oil on the beans is a result of dark roasting. Coffee contains oils and the darker you roast the coffee, the more those oils reach the surface. Heating things that contain moisture drives the moisture out, regardless of whether the moisture is water or oils, because they expand and then turn to gaseous form.
Water steams off, which is in large part why dark roasted coffee is lighter than light roasted coffee. The oils are driven out of the bean, but because of a higher boiling temperature, they stick to the bean.
The roaster forum is probably a better place for this detail, but also as coffee gets darker roasted, it gets more brittle. Brittle beans can shatter and fragment. If they are handled roughly, you'll get a lot of broken beans, which look like crap in a display bin.
The broken beans plus oil makes little post-it notes out of broken beans. They stick to glass or plastic bins and look like crap. If the bins are not cleaned out, over time, dust from the beans, chaff from roasting, etc. all start to stick to the oil that coats the coffee and the bins.
Looks like dust and oil. Starbucks doesn't doctor their coffee. In fact, they do just the opposite. They malpractice their coffee.