"That might be a good way to get yourself sued!
think that this is best left between the shop owner and the alleged maker."
No, you can't get sued for contacting the BBB. Check state laws before leaving a yelp review if you're nervous, but it's not (generally) illegal to do that either. Leave an anonymous review if you feel you must.
If you pointed out potential fraud and the owner continues to pass of the fake as real, then at the very least, you should report to the BBB. This isn't best left between you and the owner. Again, you weren't fooled; please think about the next customer.