In the future, If you want to pull arbitrary file(s) from Google N7 factory images, a useful skill set is to figure out how to use "sim2img" utility and loopback mounts (Windows need not apply).
Those system.img files shipped by Google are "sparse ext4 images" - they can not be directly mounted as a loopback, but that's where the "sim2img" utility comes in
The sequence goes like this:
- use sim2img to convert Google image file to regular ext4 image file
- loopback mount reg. image file
- grab whatever files you want (and check user/GRP ownership & modes)
It really is just that easy.
The "sim2img" utility is part of the android ext4_utils
toolset. See this XDA thread from the Galaxy S forums
for more details. (Yes the N7 system.img files from Google are also in this format.)