That they do, even if you blow away the four(!) "recovery" partitions.
I bought a Lenovo once, right around when they did this Superfish bullshit. It was the first and the last time. This thing had four extra partitions, only one of which had recovery data on it. Its not like the other three had something like a UEFI hardware diagnostic program (like what HP's been doing on their Probooks and Elitebooks for a while now) either. There was something on them, it was big enough to have a full headless OS and then some on all three extra partitions.
Being the not exactly paranoid, but not exactly clueless, person that I am, I started digging around and asking what the deal was. Funny thing is that I've yet to get a straight answer about what it was from the manufacturer. Lenovo have told me several different stories about them and none of them make sense. Fortunately the HDD failed after about a year and its been a paperweight ever since. I never trusted that machine because of any of that and I won't ever buy another from them.
Dell may have awful support and abysmal components, and HP are fucking expensive (if you want decent warranty support anyway) with only marginally better components, but neither one of them fling malware at you if you format the hard drives because the installer stubs are hard coded into their firmware.