Bert, in reading your question again, I misinterpreted what you were asking.
The one from Numrich looks to have a flat head in their picture. The correct one would be one that has an oval shaped head and would be blued. The threads are 4-40 and the total length is .310 or 3/16" is good, head diameter is .238 (15/64").

It is possible Numrich's picture is at a bad angle to see if the head is oval.