Using PowerCLi to Obtain OS Version

PowerCLi Bretheren -

I'm trying to use PowerCLi to get the actual OS version, or in the case of Linux, release. For example, I can use $vm.guest.osfullname to get the correct OS kernel but in the case of CentOS instances it returns a rather generic response: CentOS 4/5/6/7 (64-bit); whereas the actual OS is CentOS Linux release 7.2.   Even if it could just narrow it down to CentOS 7 I'd be satisfied, but 4/5/6/7 seems far too ambiguous to be of any help.

Any assistance is much appreciated.

- Karl