Good news and bad news.
Good news is with the oil pan removed (what a PAIN IN THE *** to remove!) I observed a small piece of gallery gasket material in the oil pan, at least confirming my suspicions.
Bad news is that means the gallery gaskets have gone, and I'm in for a very expensive repair job.
EDIT: Also after filtering the oil through a paper mesh coffee filter with a neodymium magnet, there was basically no metal contaminants. There was one very small piece of a silver coloured metal, but it was very, very small and the only thing present.
What is the preferred brand/supplier for replacement gasket sets?
What other items should I replace at the same time? Are some replacements "optional" ie: only replacing the timing chain if it is stretched, or am I better off replacing EVERYTHING?