Niall Brady posted a blog post a few days ago How can I determine what Antimalware Policy is applied to my SCEP 2012 SP1 client. Niall showed how to check Antimalware Policy via registry or via Configuration Manager Console. Actually there is one method more - Antimalware policy is also stored in WMI class . You can use query below to identify the Antimalware policy from WMI.

$EmptyPolicy= @()
$EPPolicy = Get-wmiObject -namespace "Root\ccm\Policy\Machine\ActualConfig" -query "Select Name from CCM_AntiMalwarePolicyClientConfig" | ForEach-Object {$EmptyPolicy+=$_.Name}
$EmptyPolicy | Group-Object | Select-Object -Property Name -Unique


Script Output