I get the same feeling, but would reputable companies like EC carbs really get involved if there was even a slight chance it's fake? I know what you're saying, but remember Briggs & Stratton did it in the past, so it's been done before.
If you read EC's blog post you'll see Mark brings up some good points, this could be very advantageous for Harbor Freight if executed correctly.
Also ask yourself who do you think the actual customer for these industrial small engines is... it's not people re-powering their log splitters, it's the kart racers and mini-bikers. So it does make some sense that Harbor Freight is actually recognizing their core customer, and attempting to provide an engine that is better suited for these applications, at least karting for now.
That's just my take on it.