I agree with the last comment. I too feel it be better to have someone look at it for you.
I am also wondering if it is not the Primary Cover plugat the bottom you are looking at?
It will show shavings and the like as they come from the Clutch Plates.
Gearbox Plug? Should be fairly clean and may be some fine minute debris on it?
I also say; let someone check knows what they are are looking at, even if it will cost you a little. I could have put in the Clutch in my FXSTC Softail and was told it was not hard to do. I am fairly mechanicaly minded but was not so sure re the spring and needing a special tool. So" I left it to someone else and all is well. How ever" I will have someone show me how to do it myself.