There's also that concept that manufacturers produce parts to one standard(better?) for OEM labeled parts and a different standard for aftermarket parts. So, a Gates OEM labeled belt might not be the same as the Gates labeled aftermarket part. Others have given examples of this in the past (in general, not Gates specifically). I.E., OEM factory Ford Motorcraft oil filters used to be made by Champion while at the same time aftermarket Ford Motorcraft oil filters were made by Purolator. For my Patriot, the OEM factory installed Akebono brake pads are completely different vs. the aftermarket Akebono pads.
Tough for us to know if Gates, Bando, Continental products are like this.
I tend to believe there is one production line and the labelling is different.