The long silver thing in front is the thread guide from the spool to the bobbin for winding the bobbin.
I don't know what you are trying to unscrew to see the bobbin.The bobbin is going to be shuttle and you should be able to see it by sliding that skinny silver plate to the left of the machine. You may need to turn the wheel to bring the shuttle into view. What a find! I love it. Thanks for the eye candy!