i was able to take both courses, due to switching programs they allowed me to take the other math and drop the mark from the original. i found 1LS3 was mostly high school review with a few new things thrown in. 1MO3 was much more difficult and had concepts that were more difficult to understand. because it is targeted to more than one field of study you will get concepts that may not be relevant to you in the future but will have to know for the course. i would recommend 1LS3 over 1M03. i have both textbooks if you would like to buy them for cheap let me know
good luck!