Found In Collection, Marked As 491

I had never heard that as a way to identify the types. Excellent images, I can see exactly what you're referring to. I might have time later today to post some better scans and see if this shows up.

I need to send that stamp in, keep forgetting...

I believe that the best way to identify type I rotary press stamps is to look carefully at the gap in the lines under Washington's ear. A type I will have the largest break while a type II will have smaller break with the horizontal lines extended. A type III will have practically no breaks. Also Johl mentions that type I examples will have an arrow shaped gap in the hair on the top of Washington's head while the other types do not. This is one of the few identification markers omitted in the 1847usa web site.

Clark