Bush Jr. received a Beretta SO-10 from Beretta USA at an SCI convention.
Its has a quail hunting theme along with engraving of his dogs and the presidential seal.
He also likes to dove hunt... looks like a Browning Citori or maybe a Winchester 101.
And he quail hunts too.... another over/under.
Bush Sr. quail hunting... can't tell what he's using but his buddy's using a Midas-grade Superposed.
And of course Cheney made his 28ga Perazzi famous with his screw up.
And Eisenhower loved to quail hunt. He often visited many plantations near Thomasville and Albany Georgia for hunts on friends' properties.
Taking a break and drinking a coke.
With a SXS of some kind.
Now with an O/U.... hard to say but its looks like a sidelock (or a sideplated boxlock).