I suppose it's possible for that particular string to get into the binary by some other means. Maybe failed anti-circumvention that checks for known strings in its own directory or something similar?
Second problem: There could be many different official executables for this game. Each would have a different hash. Provenance proving applies here too.
Third problem: Two hash values doesn't communicate the actual story as well as what this person (who may or may not be a journalist, that appears to be your assumption) chose to do.
Second solution: Not really, when you do CD releases you have a "gold master" which is the final burned CD that the other CDs are copied from. That's the one you use as the official one, as that's the one most people on PC actually have.
If the game had multiple regions (something PC games usually don't), you have multiple executables. But this happens mostly for console games, but again wouldn't be difficult to acquire a specific one for one of the ~4/5 regions there is.
Re third problem, you're probably right about this. But I'd still argue that verifying information after a finding would add more credence to the story itself and cement it better, it wouldn't take anything away from the story (unless it proved that there isn't actually any story).
> Not really, when you do CD releases you have a "gold master"
This is an oversimplification. In the late 90s / early 00s when 3D APIs were more fragmented than they are today, many games had different releases built to support different GPUs. There's also versions distributed with hardware that include checks that the PC contains the specific hardware.
MC2 had separate NA and EU releases, there is at least the chance of multiple versions from internationalization.
Are you a journalist because you're frustrated that this person isn't being a journalist...? That's kind of the same logic.
(well, "smoking gun" in quotes, because I don't really see Rockstar doing anything wrong here. Would it have been better if they had zeroed out that string?)