Yes mine is stamped 375 as well. It will take three down and one up , but wouldn't take 4 down. I can get 4 down now , but I am still not happy how the 4th tilts up . It could result In It not being picked up. With three down perfect every time , with loaded ammo . I will play with it some more later today, but still not satisfied and would not rely on it having four down and one up the spout. Although it fits much better now, it is still not perfect. It has to be perfect if you are going to use it for hunting.
The 375 I have from AHR, my old 375 , and my 458 Lott are perfect, never a hiccup no matter what I have loaded or how I work the bolt.
I want this 416 to be perfect as well. It is damn slick with three down.