I have an '05 Custom with the 518s. The bars are slightly wider with a flatter angle that turns your wrists out more than the stock wheel barrow bars. Search for posts by me. I recall posting before and after pics looking at the bars from a rear view.
That link TXCHOP refers to is for a classic, not a custom. As you probably already know the custom's bars are not that same as other Road King models. Of course my info comes from the late model customs, so if older model customs are different, my apologies.