When Cor was first revealed back in 2013 people thought he was a redesign of the 2011 driver, but in a 2013 interview Nomura made specific mention that the 2011 driver and Cor are different characters, and that while the 2011 driver was originally voiced by Hiroki Touchi, Nomura made Touchi into Cor's VA in 2013 and in 2013 Nomura also said that the 2011 driver would have a different VA now.
Fwiw Nomura was deeply involved in the casting process for FFXV VA's, he frequently gets pretty big name and popular VA's onto games he's working on especially for characters with an important role, and the VA for Drautos is Banjo Ginga, whom he shares a VA with Reeve in FF7 AC/FF7R trilogy.
There's also the case of the cropped face render of an unknown/unnamed man in the 2013 FFXV trailer who resembles Cor, so much so people still mistake that mans face render for being Cor despite Cor's face render being shown alongside that unknown man. All things considered he is more likely to simply have been Drautos's face render in 2013 before his Kingsglaive redesign when they got a facescan of real actors for the cast.