Others here may already be aware of this snippet of information/query, but I recently acquired a copy of these 2 marches in an arrangement for piano duet by none other than Richard Strauss. They have recently been reprinted by Universal Edition and are bear the opus number 127. The original full score as published by Aibl (which Universal took over), doesn't quote any opus number (see IMSLP).
When I opened my newly acquired copy, I noticed immediately that the first march is none other than the main march subject of the 3rd movement of the his op185 Piano Concerto, which the orchestra plays before the piano's entry with a counter subject!
I'm sure the Raff afficianados here probably are aware of this, but it was quite a surprise to me, as well as the duet arrangement being by a young Richard Strauss!
I was equally surprised a few years ago when the Sterling release of Raff's orchestral music which included these two marches (in Raff's orchestration, of course) first appeared. Raff's incidental music for Bernhard von Weimar was unpublished and unperformed after the play's run closed, so he revised and extended the overture to make the well known Ein feste Burg ist unser Gott Op.127 and, much later, the march to provide the Piano Concerto's finale theme. The march can be sampled at Presto here (https://www.raff.org/catalogue/catalogue_orchestral.html) - it's listed as "Music to the tragedy Bernhard von Weimar, WoO. 17 II. March for Die Frau ohne Schatten (which it clearly isn't, of course).
Thanks indeed Mark. I have to admit that I must have missed this release completely, so I have rectified that shortcoming already! I don't usually bother with piano arrangements of orchestral works (solo or duet), but felt i ought to see what Richard Strauss does with Raff, and thus bought the score!