Hi welcome to the forum.
I am a bit of a novice when it comes to trade silver. However I'm currently studying
a book entitled "North American Trade Silver , The Chain of Friendship", written by
W.H. Carter. I imagine the initials are a maker's mark. I looked over the marks listed in
this book and failed to find a W*E. I did find a reference to Silversmiths that were
mentioned in The Pennsylvania Magazine of History and Biography, Vloume 108,
2 1932. It lists a William Evans working out of Philadelphia around 1761. It's a long
shot but maybe a little more research can clear up your initials.
Good luck and post a picture of the cross if you can, I as well as others would
love to see it, Unitas