~~~ which, if so, the 10R might be under the inlay and the "5" inlay (as noted) is red and may have been 5f (Bef -- Belgian franc); possibly "emergency usage" which was not unusual.

We must also remember that a monogram can stand for anything; where K may not always be Kursaal, and a C not always casino, club or cercle... though in this case we do not know what EK/KE is.