Well this is weird. I've found three different pages on the gtx 660 (and NOT the 660m laptop card), so it's confusing.
This page is the standard GTX 660"s specs and says it has 2 GB vram:
http://www.geforce.com/hardware/desktop-gpus/geforce-gtx-660/specifications
This page is the GTX 660 "oem" - a watered down version for low-end desktops i guess. IT says it has either 1.5/3GB vram. Note that it uses a different chip, but is still a 660:
http://www.geforce.com/hardware/desktop-gpus/geforce-gtx-660-oem/specifications
And THIS article from Tom's H talks about the two different gpus- with the 660 name- and shows they BOTH have 2 GB vram:
http://www.tomshardware.com/reviews/geforce-gtx-660-geforce-gtx-650-benchmark,3297-16.html
Totally confusing. But one thing is certain: neither of them list 1 GB vram as an option. Is your friend using a program like gpu-z or cpu-z (which can also give vram info)? They are probably just mistaken. The other option is it's a fake. Here's an article on that. Good luck.
http://www.bit-tech.net/news/hardware/2014/08/28/fake-gtx-660/1