Looks like the old age ,rusty fire ring and fiber around water ways fail i'd expect 100k+
check with a steel rule for warp and see how deep the pitting is
unless it's very bad, i'd say a candidate to DIY deck/resurface it as per video link
I have a 5mm thick steel plate with emery spray mounted too but modern glass is pretty flat, i do a circular motion and also turn the head round 180 degrees to even the process out .
as i said, those old style gaskets die of old age but a new one will cope with minor imperfections and pitting .
then you need to wash the head to remove any grit etc from the work.
may take a few hours but you'd be surprised how well it works,plus you save on machine costs.
never had a headgasket fail once i DIY decked it ,and that includes z14xep corsa head which is MLS gasket and requires a very fine surface,
but accurately measuring is the first step