I am away from the full data base right now, but from what I have in front of me I can report that the following initials have been reported on Prussian Dalys:

R.S. *
E.E. *
K.S. *
J.W *
L.G (or E.G)
A.B. *
M.S.
L.E.
A.S.


(Please remember that because much of this data has been reported and not personally observed, I cannot vouch for the accuracy. Also remember that due to the nature of the stamping process, some of the stamps are hard to read - what one person reports as "A.S.", may actually be "A.B". I've noted with an asterisk above those initials that have been reported more than once.)

Ken