For transfer into the second year, the adcom requests that the applicant turns in copies of their syllabi, exams, etc. Schools do vary in courseload, but most cover the "basics" in first year (Anatomy, Histo, Embryo, Physio, Biochem, Immuno, Neuro etc.)
I don't think any school can go over all aspects of each course alone, and that's where studying for the boards comes in. I think because of that, small discrepancies aren't that big of a deal.
I don't think a lot of schools accept 2nd year transfers, but I know OSHU (or OHSU) in Oregon does, along with Drexel.