I'd stick a magnent on it and find out if its iron or aluminum ... and if your gonna pull the pan, then by all means check the bearings and the crank journals ... its to easy to do once you have the bottom end exposed not to go ahead and do it.
The only way i know to tell if you've spun a bearing without taking it apart is if it spun it so badly that the heat has turned the rod caps blue ... but once you have it exposed, just take it off and see for yourself.
You said your oil pressure seemed to be ok so why do you suspect an oil pump failure ?
If those particles turn out to be aluminum, especially with the dieseling i'd be looking hard at the pistons. Do a compression check, you might be able to narrow that down a bit ?
Hope there might be a tiny bit of help in all that ? lol
