Well, I think you have it right. The E.W. is indeed Emile Warnant. The other maker with the same initials is Ernest Wilmart but in that case it is indicated on the water table E. WILMART.You have a very good buy with this gun. I don't know if W.A.M. is still in business today but I visited the shop in the 70th in the Willem II street.
Cheers, Marc.