They wrote back.
Thank you for bringing this information to our attention. I have passed it along to our Compliance group. As you are aware, this product is not approved by FDA, but they may be implying that they follow Good Manufacturing Practice standards, which are publically accessible in the Code of Federal Regulations. The FDA database of approved animal drugs is at http://www.accessdata.fda.gov/scripts/animaldrugsatfda/index.cfm?gb=1.
From the FDA website.
That flexibilty seems like one way the quack merchants can still make their product and hint at FDA approval.