I think there have been about zero American runners that made the Olympic standard based on a time that they ran at the NCAA championships.
I can think of one Olympian that hit their only time in a US meet in the college season (Brian Hyde ran 3:35 at UNC in an open event beating professional Steve Holman in 1995 to qualify for the 1996 Olympics).
I really don't think if Manzano and Centro ran the mile at NCAA's it would have screwed them up for knowing how to run the 1500.
The tactics in a championship are to go out cautiously in the first lap or two, so the straightaway vs. curved start has no impact on tactics.
It absolutely would not have a negative impact on preparation for international 1500m races.