Here is one way to score this point with Inform:
Check saving the game for the first time: award -1 point.
That has the right effect, but it just isn't sneaky enough. Instead let us quietly keep track of how many times the player saves:
Check saving the game: change the number of saves to the number of saves plus 1.
When play ends: if the number of saves is 0, award 1 point.
Sneakier, certainly, but now we could get the bonus even if the game ends earlier on, so finally:
When play ends: if the number of saves is 0 and the score is 349, award 1 point.