Maybe you could pull the plugs and check for oil in the cylinders like the guy did,.. before and after startup.
Both the valve seal or ring jobs are huge and separate. It's worth the effort to find out for sure. Maybe you can see into the cylinders enough to check for oil. I know they have those cameras that can fit through the hole to see,.. they aren't too much money now.
I can't find that damn thread,.. I should have book marked it.