I mapped out all the places where these gullies are found, and they are all on the edges of former pole positions according to Sprenke and Baker. This would imply from a water point of view that ice or snow on the surface near the pole melted and formed the gullies so this is not much different from the current view. The main difference is it gives a possible source for the ice or snow. The other possiblity is the mechanism you say is happening now on the South pole is CO2 avalanches are making gullies there. If so then the exact same mechanism could have been operating on the edge of these former poles, so all of them might have been made from CO2. The poles provide the missing reservoir of CO2 to make it work. Also the pole positions are mapped by elliptical craters and so are plausible.