No it's not the same as a Model 4 base,but it's similar.You will find on the opposite site of where the edger attachment is the model 4 will have two bolt holes on the base.Yes there is a gasket for the muffler to base,I think Bruce has them in he's store.Also don't try to make any scene of the number it won't make any scene.As by the time the model 5's came out they were selling like hot cakes,and I don't think there was any sequence it was more about getting them out the door.
