LDAP query for machine account?

If anyone knows how to do this properly, please let me know, but for now I am trying something else as I can't seem to get it to work.

Instead, I am querying the client registry for "HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap\Domains\our_internal_domain" as this registry key does not exist if the machine is not in the domain. I guess it could theoretically be faked but it is the best check I have come up with so far to validate that the machine is in the domain and has had the Users GPO applied at least once to get the IE Zone settings pushed to it.