>But finding these unpatched and vulnerable series of machines is a hit-or-miss game with minimum chance of success

Bios update version changes or the name itself mentions 'intel ME' in the manufacturer's site for their products[1] it should be fairly simple to find computers with an older bios version.

[1] : https://www.acer.com/ac/en/IN/content/support-product/6752?b...