No one touched them yet..
All devices show in the bios config screen that the Mac-Address is 88:88:88:88:87:88
NO Systems were installed yet
All devices Are second hand
Sounds to me like someone incorrectly flashed the device, or it is due to an HP bios update.
Whatever the case, each system should have a sticker or some information on the board to indicate the mac address for that board. Use the EEUPDATE tool to correct each board.
You have a lot of work to do.