Probably most of the originals I have seen were just notched, but the lock nail was in the same position as mine. The difference is that the recall lug on the originals I have seen were not as long as the modern machined breech plugs that come with today's barrels. Consequently. I am liable to have a lock nail completely encompassed in the recoil lug, but not always. Sometimes they just catch the back of the breech plug. I also usually end up notching the underside of the barrel for the front lock nail.
My main consideration as to where to place the rear lock nail is the location of the lock bolster. I drill the hole for the lock nail from inside the bolster inlet just forward of the rear of the bolster and centered as best I can vertically on the bolster. It then goes through the recoil lug where it goes. If the recoil lug is just going to be notched, then I have to mark the notch; remove the barrel and file the notch. Same goes for the notch for the front lock nail.
I never thought of filing back the recoil lug like Fred. It would make it easier to bend the tang. I have just filed the tang where I couldn't bend it. I will have to think about changing that part of my build. Hummmmm......