But even if its the latter they do, at least if the game is a faithful recreation. Games are not 100% spec'd out before the coding begins. There are iterative processes where developers implement parts of the game, and go back to the drawing board to rework the code and data (assets, levels, configurations, etc) based on testing. The game is a result of all of this trial and error.
Even if a game were rebuilt from scratch, the people who contributed to the original development effort share in the end product.
"Deserve" is subjective. But if we consider development efforts that make the end product the way it is to be deserving, then the latter absolutely deserve credit.