You stated the path so I am assuming that you are looking at the correct /library folder and not the one under the username.
If it is not there then that is most strange as this is common to all Mac versions as it contains (as the name implies) all of the core services for the operating system.
One other thing you can look at would be the version of Safari that is on the system. If you browse to the /Applications folder, right-click on the Safari.app and select to show package contents. Expand the Contents and in the listing that opens up look for a version.plist, in there you will see the version of Safari that was being run on the system. This should correspond to a unique OS version, with the exception of 10.10, 10.11 and 10.12.