All default Brightman Designs styles are saved here (similar on your machine), C:\Users\mike\AppData\Roaming\SketchUp\SketchUp 2020\SketchUp\Plugins\ConDoc Tools\styles. The ConDoc Drawing sets do not carry the styles with them since the default styles are saved locally on your machine. Any custom style you create that is loaded into the drawing set will travel with it.
So, you can feel free to modify those ConDoc styles, but you might consider making a backup. Or probably a better idea, you could create your own styles and load them into a new custom drawing set. Just back everything up so you don’t lose the defaults!
Let me know if that helps!