I have recently changed from an all Dell shop to an all Lenovo shop. I've gotten used to the model under system inventory being the actual model of the machine. With Lenovo I get a combination of seven digits. This is not a huge deal. When searching for drivers I can enter this number and it will find the drivers I need on their site.
To resolve this I created a custom inventory rule with the information below. This will get the system model on Lenovo machines.
ShellCommandTextReturn(powershell Get-WmiObject Win32_ComputerSystemProduct | Select Version)
After the machine inventories this will now place a new field under custom inventory.