Well, this is not as clear as it could be but its from the FDA's website's FAQ section:

"Is it illegal for a foreign pharmacy to ship prescription medicines into the U.S.?

"It is illegal for anyone, including a foreign pharmacy, to ship prescription drugs that are not approved by FDA into the U.S. even though the drug may be legal to sell in that pharmacy's country. Under the scheme that Congress established to ensure that drugs are safe and effective, drugs are tested and test results are thoroughly reviewed by FDA scientists. U.S. law also requires that products approved for sale in the United States have their formulation approved by FDA, be made in a plant registered with FDA, and be produced under quality standards enforced by FDA.

"Prescription drugs available from a foreign pharmacy that are products that FDA has not approved; products with similar, but not identical formulations as FDA-approved products; products not made under the quality standards required by U.S. law or labeled according to U.S. requirements; or products not stored or distributed under the quality conditions required in the U.S. cannot be legally sold in the U.S."

So the question is, for example, is generic Paraxotine 20 MG from India the same as generic Paraxotine 20 MG (Paxil) from the U.S. and therefore is allowed to be imported under this rule. Or not because it was not manufactured in an FDA approved facility???? My guess is like you said probably not, but its rarely enforced.