Milodon 31000, anyone have it?

Is that just the regular mid sump A body swap pan? If it is then that's what I have on my 67 Dart. Started with an aluminum fabbed pan that my dad found on Ebay, but the pan rail welds cracked and leaked oil all over the place. Went with the Milodon because it was steel and have had no problems since, though I'm using the stock pan gasket/windage tray, not the Milodon one. Why did Realwing say to avoid it?