SGC would probably just knock it down a couple of grades. The guys across the street would probably give it a MK (pencil/pen mark) qualifier.|
Authentic is for cards that have been tampered with for improvement sake (trimming, recoloring, rebuilt corners, etc).
#1 in 1959 Topps. Officially known as Assassin according to stanthemanfan 3/31/2014 and god of minor league basketball according to cammb.