I have no idea. I never paid much attention to these pans. I bought one when I first started collecting and it is still around here somewhere I think. Quite frankly I didn't know there were any variations to this pan until I read this post. I've seen a bunch of them, but just never paid much attention to them. I'm going to have to keep my eyes open for one with the lips, as I'm almost sure the one I have is the tab end, no spout variation.
Harry