Almost, yes. It should be close enough as an estimate.
If you want to be precise, one thing you want to be careful about is that not every fuel releases the same amount of energy per kg of CO2. So you should be comparing to the CO2 released by whatever is being replaced by the biofuel (most likely fossil fuel), not the biofuel itself.
Another consideration is how much CO2 is released by the production of the biofuel compared to what it is replacing. Since farming equipment, transportation etc. all could produce CO2.
I strongly prefer GOG to the point where I often don’t buy games that are not on GOG.
That being said, one reason to buy from Steam is steam workshop. So if I want a lot of mods, I may buy from Steam even when available on GOG.