Okay, buyers from St. Louis firm Whelan-etc.-Hutchinson visited New York in 1902 staying at the New Amsterdam Hotel:
https://books.google.com/books?id=vHQoA ... rk&f=false
There are also references to the company in 1909. So, this might match the era for The Sweetser Company of New York listed as "Gold and silversmiths c. 1900-1915" using the mark "S & E" in three separate boxes conjoined in the horizontal frame. It is in RAINWATER 4th edition (drawn sample) and on this site in a less ornate style found here:
https://www.925-1000.com/americansilver_S7.html
Of course, your second boxed letter is hard to visually match-up here.