I was interested in how Civ III scores for conquest victories by date, and so put together a little map to test on. The two civ starting locations are right next to each other, one a mountain, and the other tundra, with 1 mountain inbetween. The rest of the map is ocean. Just by building the first city you automatically get a conquest victory the next turn. So I kept reloading till I was the one starting on the tundra, saved the game, and then started jotting down scores for different conquest dates.
It seems that it scores by date. On Deity, for the 50 year turns the score goes down about 300 points per turn, or 6 points per year. The 40 year turns vary by about 240, again, 6 points per year. I tested in the 1000 BC and around 500 AD ranges, and it consistently was 6 points per year. By the way, a conquest at 3950 yeilds 36060 points! The only way Im going to get on my high score board now is with some file editing
ps. just checked the highscores.cv3, I thought it would need a hex editor, but nope!