I would tend to agree with you that American Samoans do not have to worry about deportation or denial of admission. However, in terms of naturalisation requirements, they follow the general rule for other permanent residents - that is 5 years of continuous residency and a good moral character.US noncitizens nationals can apply for citizenship too. Just don't know how their eligibility are different from ours. Apparently they don't have issue such as abandoned GC, deportable offenses.