Typically an overlooked fluid on used vehicles. I also suck the old fluid from the reservoir before bleeding so that I am only pushing fresh fluid through. Might as well always get a set of bleeder covers as every vehicle that I have purchased has had them either missing or rotten.
Yes, I also had to replace those. I had a few missing and replaced them later on. I did pull most of the fluid out with a turkey baster put it had a crack in it and that part was more of a mess then.