Why even peel a potato? Just wash it and chop it, done.
This depends on the condition of the potato. When it's really covered by dirt and with blemishes, it's best to peel them so they don't mess up with the appearance and flavor of food. It also depends on the food, since the potato skin can get in the way of eating them. Although, with curry, it's trial and error in determining if you want to peel or not and whether in interferes with the consistency of the curry itself.
The 6thDesDiv are using, what I assume is, the russet potato. So it's best to peel them. Unless you're making fries, baked potato, or some sort of fried potato.
That being said, I generally prefer the small red potatoes for curry since they have thin skin and they don't really need peeling.
Edit: Just looked it up and, if you do peel them, keep the skin and roast them for snacking.