Its just general bits of swarf from around the engine. Thats what the filter and magnet are there for. I've seen them much worse than yours as well! One had a whole gear tooth stuck to it. Little bits that you can hardly feel between your fingers are nothing to worry about. Just clean it all off and check it again next time.
Looks like you may be suffering the parts bin problem. The engine case appears to be the type requiring an o-ring. the machined area around the oilway is where it would sit. The base gasket looks like type that does indeed require just sealant, although the hole shouldn't be blocked up with the stuff. the base gasket that fits with an o-ring has a bigger hole that sits around the sealing ring. I'd have a word with your dealer. Having the recess for the o-ring means that the gasket and sealant won't seal alone. It'll need a ring in there to fill the gap. Probably the o-ring and suitable base gasket is the better alternative. I've checked the parts diagrams and neither really tally with your 2001 748E though. Have you got the heads with the lower exhaust cams? 5 bolts holding the rocker pin covers in place? or 4 as per the "traditional" heads? Ducati are showing the 2000 models with o-rings and 2001 without.