Yeah, those are stock. They're designed to only come in contact when there's a heavy load on the truck. It helps to support the weight when loaded and doesn't make the ride rougher when empty.

 

Yep, mine are stock. The only thing changed/added on my rear axle is the MH rear diff cover, Rancho 9000 shocks, and the Lazarsmith traction bars.

..

 

JC Whitney sells some "traction control springs" which are essentially half leaves mounted on the forward half of the rear leaf springs. I tried a set and they didn't do the job, although they did help a little. The little Tuff Country traction bars did work however, also from Whitney.