GB is the country code of British patents. For example: GB201214280 is a British patent number. Its format is gb nine-digit Arabic numerals. The format like yours is wrong, and it is impossible for other countries to use it. There are regulations for starting with gb, and generally the two country and province codes are directly followed by Arabic numerals. So this should not be a patent number. There are many counterfeit and patented products out there, so please be careful.