Every book on this site holds a licence from the Gaming Commission of Ghana, and the Commission publishes its list of licensed operators. That list is the only thing on the internet that decides the question. A licence number in a website footer is the operator writing about itself, a licence number on an affiliate page is somebody copying that, and neither is the register.
What the register gives you is a trading name, the class of licence, and the dates it runs between. What it does not give you is a licence number. That is worth knowing before you go looking, because it is the reason this site treats "does it publish a licence number" as a question the operator alone can answer, and the reason a number quoted on a review site cannot be verified by anybody.
The class is where the interesting mismatches live. More than one book on this register holds a sports betting licence only while running a full casino, live dealer floor and crash games. That is a difference between what the register records and what the product does, and it is a fact rather than an allegation: the Commission lists what it lists.
Ghana issues its permits annually, which is why a licence number seen in one year and a licence number seen in the next can both be genuine and different. Several brands here have a run of numbers across successive years, and an affiliate page quoting an old one is out of date rather than wrong. The current one, where an operator publishes any, is on its own footer.
One name to be careful with. Lotteries in Ghana sit with the National Lottery Authority rather than with the Gaming Commission, so a lottery product is licensed by a different body and does not appear on the betting register at all.