You can use the
-l flag to list your privileges.
If no command is specified, the -l (list) option will list the allowed (and forbidden)
commands for the invoking user (or the user specified by the -U option) on the current
host. If a command is specified and is permitted by sudoers, the fully-qualified path
to the command is displayed along with any command line arguments. If command is
specified but not allowed, sudo will exit with a status value of 1. If the -l option
is specified with an l argument (i.e. -ll), or if -l is specified multiple times, a
longer list format is used.
If you're not in the file, you should get the "not in the sudoers file" error you saw on the other machine.