I have the impression that a lab accompanied each lecture, i.e. 4 labs -- 2 of gchem and 2 of ochem. The only exception to this I've encountered is a single lab course encompassing the material from 2 semesters of ochem.
If you're concerned about what lab courses you need to take for med school, the 2 labs for gchem and 1 lab for the first semester of ochem seems to be the standard, with some requiring the second semester of ochem. Best to check the med schools you plan to apply to.