If they have lice, you would probably find the adult lice in their fur.. Also I think louse eggs are very adhesive to fur/hair, so if the spots fall off from you lightly brushing the fur with your hand then its most likely that they are dust from the shavings
It is hard to tell from that one picture but you can buy a fine toothed comb and go over the fur with it. If they have lice, the comb will pick up eggs/adults. Have they been excessively itching recently? You can tell it is eggs and not bedding since the eggs, when pressed between your fingernails, will leave a blood speck. Treatment for lice is pretty simple so the faster you treat, the easier it is going to be.
Thank you both for the replies and additional suggestions. After getting to examine them in person, it was in fact lice. Itchy, moving, bothersome lice (and their sticky eggs). The poor babies have been treated and quarantined. Thankfully the treatment is simple enough, as was mentioned. I am just impatient for these next few weeks to go by!