I have an ADM file called defaultprinter233.adm which I have added to the Administrative Templates. I have unchecked in View, Filtering, the Only show policy settings that can be fully managed. According to what I've read elsewhere, now an Extra Registry Settings folder should appear under Administrative Templates. I am unable to find it, nor anything that would refer to this policy. The adm file says:
CATEGORY "Software\Microsoft\Windows NT\CurrentVersion\Windows"
KEYNAME "Software\Microsoft\Windows NT\CurrentVersion\Windows"
DEFAULT "Lexmark C762 233,winspool,Ne06:"