The official Android 4.2 digital Clock widget is re-designed by developer. With the new layout, it comes with the mixture of bold and regular font, no the light Roboto font. There are also some issues while using the clock app, such as incorrect stopwatch notification, and randomly crash and freeze if click the Alarms button.
If you want to still use the old stock clock widget on Android 4.2, Fixed 4.2 Clock Widget by Alamo Apps is what you are looking for. It offers a simple solution to fix the new half bold-half thin jellybean clock, and gets the font to your liking. The app works fine on a launcher and is compatible with lock screen.
I have installed it on my nexus 7 tablet. Aside from the above features, I am also easy to see my alarm times. If it support adding shadow and shadow color, that would be more great.