Xcode 5 Is it possible to change the font and size on the storyboard?

You can change the font (choosing from those in Xcode) the size of the font and color, everything from the storyboard

check this screenshot:

Open the Utilities Panel on the right and view the Attributes inspector by using the shortcut key ⌘⌥4 or selecting the shield looking icon at the top of the panel, and when a UILabel, UIButton, or other object containing the desired attributes (Font, color, etc) will show in the inspector window on the right.

By clicking on the icon inside of the "Font" attribute you bring up additional options including the font style, family, and size. You can also select one of the new Dynamic Type styles (Body, Caption, Headline, etc) in this attribute inspector panel.