The most common answer for black spots appearing on your cats lips, nose, or eye margins is that it is a condition called lentigo simplex, and it is not a form of cancer. In fact, it is completely harmless, just like human freckles.
That said, one cannot assume that every black spot on your pet is harmless, this is just the most common scenario for orange-colored cats. Always have your cat checked out by your veterinarian to be sure.
This condition is characterized by small (1mm or less) lesions that may appear close together, discoloring a larger area. The lesions are flat, are not painful or itchy, and do not have any associated redness or other discoloration.
Please check in with your veterinarian It is always wise to check out any new finding with your veterinarian to rule out something serious, especially if the spots are at all raised, inflamed or causing your pet discomfort. There are many conditions of the nose and lips that are more serious. Your vet can provide a hands-on exam to guide your pet's care.
If your cat is one to "freckle," expect more of them as s/he ages!
Related Reading and Photos of This Condition:
Photo of orange cat lentigo
Several comments from VetMed Viewers about this condition
(click "comments" link on linked page)
Lentigo Simplex in Humans
Photo credit: "Beaker" by iLoveButter on Flickr