I downloaded the 5.1 version (VMware-PowerCLI-5.1.0-793510.exe) . I had to uninstall the old version, and then install the new version (otherwise, all it asked me was to "Repair" the installation, and it didn't update). Now it does say 5.1. However, running "Get-Complaince" causes a "Process is terminated due to a StackOverflowException, and then PowerCLI closes.
PowerCLI Version
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VMware vSphere PowerCLI 5.1 Release 2 build 1012425
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Snapin Versions
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VMWare AutoDeploy PowerCLI Component 5.1 build 768137
VMWare ImageBuilder PowerCLI Component 5.1 build 768137
VMware License PowerCLI Component 5.1 build 669840
VMware VDS PowerCLI Component 5.1 build 1012428
VMware vSphere PowerCLI Component 5.1 build 1012428
VMware vSphere Update Manager PowerCLI 5.1 build 782803