Yes, you need to specify the domain. Either by setting SIP_DOMAIN variable or if you are using domain module or don't have the variable set indicating user@domain:
sipproxy:~# kamctl ul show saghul ERROR: domain unknown: use usernames with domain or set default domain in SIP_DOMAIN sipproxy:~# kamctl ul show saghul@sipproxy.saghul.lan 404 AOR not found sipproxy:~#