Yes, it is differant to retire by prolonge. A prolonge rope is the large rope usually seen wrapped around the prolonge hooks which are mounted on the trail of the gun. To retire by prolonge, the rope was afixed usually to the trail and pulled out of harms way, by the gun crew and often, infantry soldiers detailed for the duty. This procedure was used in an emergency when they needed to retire in a hurry. The gun was manhandled to the rear when horses could be harnessed to the gun.
I have not heard of retiring by recoil. A gun does recoil rearward when fired but not far enough as to remove the gun from danger. To use this as a method of retiring would result in the gun being captured by the fleet footed attacking enemy.
Ron