I figured out a decent solution using get_field_object and update_field.
For anyone passing this way, you want to pass the value of the [‘value’] index of the retrieved object to update_field.
$layout = get_field_object('field_name', $post_id);
...
update_field('field_name', $layout['value'], $inserted_post_id);
I’d love to have code that can iterate through fields w/o my having to hard-code the field name, though.
