4779 is a 750 double-pumper. The -2 is simply a revision number. Can't help with the 0 0 5 7, are you sure it's a date code? If it is, according to the March issue of Hot Rod, 005 is the Julian date (5th day of the year) and the '7' is for 1977. The artist redering in the magazine only shows a 3-digit date code and all numbers are together, not spaced out. Four digit codes may be different but I'd think they'd all be together without spaces.
