Download CPU-Z:
http://www.cpuid.com/downloads/cpu-z/1.68-setup-en.exe
Install/execute it, then go to "mainboard" tab and see if the info in "model" field is the same as the one belonging to your laptop.
EDIT: Lenovo's datasheet of your laptop doesn't give an exact info regarding which mobo it has (http://www.lenovo.com/shop/americas/content/pdf/system_data/g470_tech_specs.pdf)
It only points out it has a Mobile Intel HM65 Express Chipset, so see if at least it's the same chipset, you will find that info in "mainboard" tab.
According to the datasheet your laptop model should be the 4328-27U, maybe googling around with that code you might be able to find out the exact mobo your laptop should have.