Intel HM87 (Lynx Point since it’s too much to type and it won’t let me copy and paste it here’s the main board maybe that could help . It had a gtx 960m , i7-4720hq , I believe 8gb ram.
GPU is soldered and cannot be upgraded according to This
Also, from pictures from the review here show a GPU under heat sync but the GPU appears to be soldered to the motherboard.
For more confirmation, you could open up your laptop and see if the GPU is soldered