WOW!!! coolest find of 2013 in my book.
That badge is unlike any other Excelsior badge I've seen! It is of the pattern of the Michigan City Excelsiors (post 1916), but it looks like "Arnold Schwinn" text was molded over or re-stamped with it being raised. There are some pre 1916 that say "mfg Excelsior Cycle Co, Chicago, ILL" that are of the same pattern also. This badge could have come about from when the split first happened in 1912 until the move to Mich City. But Schwinn could have held on to the badge punch and used those for a number of years.
The fork is consistent with teen Schwinn literature.
Did you pull the cranks to see if they are dated?
Congrats on an epic bike!!!
Chris
I think the 1917 Schwinn lit should be a good place to start for saddle choice.