This is working and I like it! I can use as a template for registry settings. This is what I was using, I think it is from the canned DISA content:
not exists 1 whose (conjunction of (exist values “DontDisplayLastUserName” whose (type of it = “REG_DWORD”) of keys “HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\System” of it) of (if x64 of operating system then (x64 registry; x32 registry) else x32 registry) and conjunction of (if exists key “HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\System” of it then (if exists values “DontDisplayLastUserName” of it then (concatenation of substrings separated by “%00” of (if it ends with “%00%00” then preceding text of last “%00%00” of it else if it ends with “%00” then preceding text of last “%00” of it else it) of (it as string) of it = “1”) of values “DontDisplayLastUserName” of it else false) of key “HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\System” of it else false) of (if x64 of operating system then (x32 registry; x64 registry) else x32 registry))