I also show the 5.7.0.0 in my environment under Add/Remove programs. You can confirm the 6.0.0 is installed by looking in "C:\Windows\SysWOW64\ContegoSPOP" should see 6.0.0 directory. It looks like they forgot to update the registry (HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\SolarWinds Log & Event Manager Agent) with the new details i.e. DisplayVersion and InstallDate.
*Note paths may be different on a 32-bit OS
