With the milage you have on it thats normal. Of course you will have clutch material from the converter clutch and the tranny clutches in the filter that you cant really see from normal wear at 120k. I have seen this many times before. Change the filter and fluid and get another 30k out of it. I see tranny's look like that at 30k with just tiny particals that are normal. As long as its no bigger pieces then I would service it with a filter and let it go. Ron