Actually this was the second oil drain since putting it back together. The first was after about ten minutes of running, to try and flush out the chocolate milk.
The head is aluminum, so I don't expect any of the particles to be from there. With the rust in the cylinders, I expect that some of the particles, all microscopic, no slivers, are probably casualties of beating the rust out of the system.
I will do another oil change and use a premium filter in about another 800 miles. There must have been some microscopic particulate generated with water in the oil, the rust, the machining and who knows what all. If I see anything of any quantity next time, then I will be alarmed.
My immediate problem surrounds getting my power back. I expect the timing chain to be one notch off. I further expect that I can remove the valve cover, which I must do to check it anyway, and then remove the tensioner and move the chain a notch, without removing the camshaft front cover.
Thanks for the response,
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in