for future personal reference: just compare filenames to grade CSV to make sure no grades are missed.

gradecheck.py

import csv, glob
examfiles = [x[0:4] for x in glob.glob("*.pdf")]
with open("count.csv", 'rU') as grades: 
    gradelist = [x[0] for x in csv.reader(grades, dialect=csv.excel_tab)]
# but csv is shit so:
grades = [x[0:4] for x in gradelist]
missinggrades = []
for i in examfiles:
    if i not in grades:
        missinggrades.append(i)
wronggrades = []
for i in grades:
    if i not in examfiles:
        wronggrades.append(i)

print "exams without grades: " + ", ".join(missinggrades)
print "grades without exams: " + ", ".join(wronggrades)