I love my T206ers, but not in that kind of way, I'm talking about finding out exactly what year in which they were printed.
SGC usually puts a date on a T206 card, either 1909, 1910, or 1911, but then sometimes SGC just puts "1909-1911." Is the "1909-1911" card graded right before lunch or quittin' time?
PSA doesn't bother, and just puts "T206." Why doesn't PSA put a date on it? To save time, or because its not clear whether it was 1909, 1910, or 1911?
Is dating a T206 card an exact science? Is there some sort of formula to follow? Or is it a complex inquiry due to a variety of factors, such as back, factory, set #, etc? What formula/criteria does SGC and others use?