For peace of mind, ask if they can supply original sale receipt and if you buy, get a bill of sale. Using the CPU in another machine is fine, Vpro can be disabled from with the motherboard bios.
+1 das stig
Are the systems Desktops or laptops? Laptop will have some additional features to protect against data lose like shutting down from the Bios. However if it is a desktop the main features are remote access for the business IT. There is some software that allow them to log on and access other system within the network and update drivers, Bios and check system configurations.