Wouldn't it just be easier and cheaper to print a barcode on each product and let customers use it to verify the authenticity of the product using a web site?
this requires a mean to identify where the unique good is (if it exists at all). would rfid fix this? hmmm shrug
E.g. in web system you can assign owner to barcode (product). Different scenarios if owner is known before purchase or assigned later. All other trials to validate product id as unique should fail and client might request return of money.