lpd(8) does not accept another port number as documented in the manual
page. Looking at the sources for lpd, lpd does not recognize the additional
port arguement. in lpd.c (main())

                sp = getservbyname("printer", "tcp");
                if (sp == NULL) {
                        syslog(LOG_ERR, "printer/tcp: unknown service");
                        mcleanup(0);  
                }       
                memset(&sin, 0, sizeof(sin));
                sin.sin_family = AF_INET;
                sin.sin_port = sp->s_port;
                if (bind(finet, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
                        syslog(LOG_ERR, "bind: %m");
                        mcleanup(0);
                } 

Later in the code it make sure the port is a reserved port (lower than 1024)
for security purposes, so even if we could change to port number it would
only work for reserved ports.

Fix: 

remove the port# information from the manual page.
How-To-Repeat: 
# lpd 4
# netstat -a