Exposed nails must be sealed. I just put 11 squares of arch. shingles
on my new garage. I am not an experienced roofer and used a nail gun.
I took my time but wound up with 5 halfway exposed nails, plus 2 for
the final ridge cap shingle. I used roofing cement to seal each nail
and the cap. I would be ticked if there were 70 and I paid someone
else.