I would probably call him a light bay to be honest, but he looks like he has a more golden sheen to him and I know someone had a horse that looked very dark and reddish like that that turned out to be buckskin through testing. You could test him for cream for $25 to be sure. Horse Tests
Do you know if the palominos that his sire threw were out of buckskin or palomino mares? That would help.