First off, I meant "an addition" above, not "and addition".
Okay, some interesting tidbits..
-Every version of the rules (even the rough draft version) except the 1961 printing (which was the second printing of the first edition, but not the same) had this or a similar provision for declaring a draw, which every version strongly implies is somewhere between a win and a loss.
-In no version is there any credit given for any country other than the winner in games where there is an actual winner.
-In every version with a provision for a draw, all the players left on the board at the time of the draw get credit for the draw.
-Here is the most interesting point. Except for the rough draft version (1958), the original printed version (1959), and the newest version (4th edition, 2000), in every version there was a provision for a "Short Game" in which a predetermined amount of time was given for each game, and once that time limit had been reached the country with the most centers was declared the winner.
This is very interesting when combined with the fact that, until the 2000 version, it was specifically noted in EVERY version that when the original game session ended, the game was over and either there was a winner or a draw. It is my opinion that the advent of the internet actually managed to delete this from the rules.
Technically speaking, there was absolutely no provision given for play-by-mail in any version. What I mean is that, until 2000, the rules specifically stated that you played the game face to face until someone won or the session had to end, which would result in a draw.
Incidentally, I got all this information from a site called diplomacy-archive.com, which also has some discussion on house rules, paradoxes, variants, etc.