An essential Part when dealing with Objects is Uniqueness. VMWare Workstation Fles could be Spread widely across your drives and the Directories Location of a VM can change over time.
Having that Said, you could have 2 VM´s with the Same name or 2 VM´s in a single directory. As a bets Practice when Programmin with Managed Objects, it is always good to have a Unique Identifier. VMware Workstation uses the uuid.bios Parameter to honour this.
labbuildr also uses the UUID, and it is exposed by get-vmx. you could also do a Get-VMXUUID to just retrieve the UUID
Get-VMXUUID [-VMXName] <Object> [<CommonParameters>]
Get-VMXUUID [-VMXName] <Object> -config <Object> [<CommonParameters>]
Get-VMXUUID -vmxconfig <Object> [<CommonParameters>]