I wrote a plx script to get the most common phone model names and hash them in the same way that our metrics do here:

https://uma.googleplex.com/p/chrome/histograms/?endDate=20190109&dayCount=28&histograms=EasyUnlock.AuthProximity.RemoteDeviceModelHash&fixupData=true&uniqueUsers=true&showMax=true&filters=platform%2Ceq%2CC%2Cchannel%2Ceq%2C4%2Cisofficial%2Ceq%2CTrue&implicitFilters=isofficial

However, by far the most popular model name seems to be the empty string! After a bunch of digging around, it seems pretty likely that a large chunk of these come from sign in:

https://cs.chromium.org/chromium/src/chrome/browser/chromeos/login/easy_unlock/easy_unlock_service_signin_chromeos.cc?rcl=09942f4374744a8849dc7cf9c8e4202ab65f47c6&l=545

We should see if there's a way to get the device name from outside the user profile without violating privacy/security principles.