OS X Yosemite version is a weird number
I noticed that your friend's installation appears to be in Dutch, so I suspect that this is a localization / language issue. If you search the web a bit for "yosemite 135122" you will find others with non-English OSX installations reporting the same issue. It seems like this particular string was not properly "translated" into other languages. So other than a strange "About This Mac" screen, this should not cause any issues.

10.10.3 is out already; maybe upgrading will fix it?