I did a quick test in which I verified that the rowid values in the link table (in this case, linking a family handle to its child_ref handles) do indeed correspond to the order of the children as shown in the user interface. I’m not a python developer, but I can see in the code that it is creating the link rows within a construct headed by the statement “for child_ref in ref_list:”.
By the way, when working with the export, you may have noticed that some column values are not populated; see this thread for details.