If two colleges have the same prestige, does the higher SAT score mean more emphasis on SAT and less emphasis on GPA?

With respect to the original question, maybe.

For example, it was probably the case for USC versus UCLA, where their frosh profiles indicated that USC frosh had higher SAT/ACT scores, while UCLA frosh had higher HS GPAs, and various other indications also suggested that (general UC policy de-emphasizing SAT/ACT relative to HS GPA, and USC’s historical chasing of high test scores to climb the rankings over a few decades).

But it may not necessarily be the case for other college comparisons, especially if you have only SAT/ACT scores and not HS GPA to compare between the colleges.