I think that
would require disambig to be substed.
Probably not true as other magic words such as __TOC__ work from
within templates.
Placing the table of contents doesn't involve putting a flag in the
database, it's just taken into account when parsing the page before
displaying it. Marking a page as a disambig would have to be taken
into account when saving the page and I don't think transcluded pages
are even looked at during the process unless they are substed.