I've been using clen for well over 12+ years and in all that time, I've never come accross counterfeit clen tabs. I've heard of fake "research chem" stuff but never pharma grade tabs. I don't know of a Genesis brand but I don't see why anyone would go out of their way to bootleg a compound that is cheap enough as the real deal. It just wouldn't make financial sense from a bootleggers standpoint to make tabs, bottles, and labels when clen is cheap and readily available?!
Since this will be your first run with clen, you'll probably notice sides around 80mcg or so.