Config.history.controls = false;
Config.history.maxStates = 1;
Either way, you only need to use one of those options.
config.history.controls = false;
No. The config object is a deprecated v1 compatibility shim. See: Config.history.controls.
Huh? It seemed to work fine when I tested it. Is the difference Config rather than config?
It worked because, as I noted, it's a compatibility shim in v2. As I also noted, it's deprecated, which means it's on life support (i.e. depend upon it at your own peril).
The difference between the base objects is, yes, the spelling (i.e. Config vs. config). That is, however, not the only difference. If you're using config because you're familiar with the v1 object or are just looking at outdated examples, I suggest looking at the SugarCube v2 upgrade instructions, specifically, and its full documentation, in general.