For the most part, not necessarily. According to the Asus ROG forums, yes, but it isn't worth it:
https://rog.asus.com/forum/showthread.php?78626-ROG-GR6-processor-questions
Most of the time, "mobile" Intel processors are not meant to be upgraded, the same can be said for Nvidia GPUs with an "M" at the end of the number (such as the GTX 960M).
These devices are meant to be similar to a console, but are often too expensive for the performance you get and thus most would recommend building something on your own.
You CAN however upgrade the HDD to perhaps an SSD and the RAM if you have let's say 8GB, but the gains would be negligible.