The bid/ask spread on the gold bars at the same dealer is close to 30%. The other markup is peanuts.
That's why it gold as the "investment" is mostly sold via day time infomercial on second rate TV networks ( the ones that currently broadcast in 480i ) and second rate cable channels as well as promoted by the likes of Glenn Beck right next to "have your own seed bank so you can plant your own garden for food when the economy collapses".
JPM made a lot of money serving those outfits but for it gold bar is just a blob of a certain weight and certain purity.