There certainly is a marked difference in the finished product. I built a 8 posted shed at out worksite last winter. I randomly DB'd 4 of the posts - I can already tell which was DB'd.
Perhaps Drawboring is related more to the MC of wood? An experience framer might chose to 'straight drill' a tenon on a piece of 100 yr old material?
I'm surprised, Don, by the opinion of the fella you speak of. If it didn't happen on the barns in that area and era, where was is standard practice?
From my experiences working with (primarily) swiss carpenters, DBing is not a practice.
brock