The 6.2 is an indirect injection engine. Anything below 150° is considered cold and glow plugs are needed to help starting.

The 6.2 with working glowplugs fires up so fast hot or cold it is amazing. With a good working glow plug system the starter will be used so little that it should last a very, very long time. Same with the batteries. Do as you wish. It is your truck. However, I would hook up an automatic system. Once set up it makes one less thing to worry about.