Yes, N 00
7983 = DIN 7983 just as N 00
7981 = DIN 7981.
And no, 002203 cannot be directly translated into diameter and length. Mercedes made sure that owners and service stations could not just go to a hardware store and by inexpensive screws , nooooo you have to buy them with a 500% mark up from a dealer!
Seriously, Mercedes provided two sets of books, (1) a DIN survey list that shows a drawing of the part and indicates what is is, e.g. a nut, a bold, a clamp, etc., and (2) a code list that translates the MB
Norm number into a description of size, material, and surface treatment, etc.
Here are copies of what these lists look like. Note that the Code List = Schlüssel-Liste Nr. 7, that means that there are many more, I believe it went up to Nr. 10 and having just one is often not enough. There are ways to get your hands on number 7 but I prefer not to describe this publicly.