You are correct.
If you're using a shell such as bash you can tell it to have * match on dot files as well as usual ones:
shopt -s dotglob
rsync -rt source_dir/* target_dir/
I've added a trailing slash to the target so that it's always considered as a directory - even if the wildcard expands only to a single item. At the other end of the scale, you may encounter problems with the shell enumerating the results if * matches a (very) large number of files.