We examined the variation in Force and Motion Conceptual Evaluation (FMCE) preclass scores according to the type of physics class a student had in high school. This was done for students who had taken Physics 1 at a highly selective university. The majority of students had taken an Advanced Placement (AP) physics course, allowing us to examine in detail the correlation between FMCE score and both taking an AP course and the score on the AP exam. We also carried out regression analyses to determine how FMCE prescores and course final exam scores depend on taking an AP course and AP exam scores, when math SAT scores are included as a proxy of students' general level of college preparation. Students who take any type of physics course in high school outscore those with no prior physics experience by 26%, but students who have taken AP physics do not significantly outperform those who have taken a normal high school physics course--many students who took AP physics scored very low on the FMCE. Furthermore, while taking AP physics predicts a statistically significant increase in FMCE scores, the effect size (0.30) is smaller than that seen for math SAT scores (0.47). We found that AP exam scores were not correlated with final exam scores after controlling for math SAT score. In all, the data indicate that, though taking an AP physics course is correlated with greater conceptual understanding of physics, scoring well on the AP physics exam may be a rather weak measure of conceptual understanding of physics or the mastery of physics one would expect students to achieve from an introductory university physics course. This work was done with an unusual population. Further studies are needed to determine how general the weak relationship is between AP exam performance and FMCE performance that we observed.