How to tell a "fake" ECU from a real one

I will say that I have used the 7500 high Rev control unit for about 3 years and found it to be a very good unit. I use it on my 340 with 66 to 67,00 RPM shift points when I'm getting it. I would buy another one in a heartbeat. And what's not to love for 45 bucks or whatever they cost