I got the repro louvres from Ames and they look great. They fit just as well as the originals. Mine is a 68, but I think they are the same. As far as placement - have fun. I drew a template on paper - marking the holes on the paper and then using a center punch to mark the sheet metal - one louvre at a time. This worked pretty well, but it is definitely a tedious job. I would highly advise drilling before paint.
Wendi