I think the casino will not want to say whether they are buying a source code or rent from the other gambling provider because I believe that will be their secret, and they don't want the public to know one of their secrets. Besides that, I think they will not tell us how much money they use for the source code, and they perhaps only tell that they spend some money to rent the code. At least, they need to keep one of the secrets for their business because they don't want their competitor to know about that secret.
Sometimes they'll say if it's from a provider or licensed I remember bitcoinvideocasino did it to clear some doubts after another site used their slot game and there's not much point to keep it a secret when casinos use the same slot games from the game providers. I think it's much better if they announce it early if they bought a license or not so there won't be any confusion because if not they could end up ruining their reputation similar to betking.