Hello, P4NZ3R (and Greg and ostland)
Bare in mind that there were different SS songbooks, and different editions of them. The aforementioned SS songbook (by the RFSS, 9th edition, 1941) actually contains almost no SS songs and reminds of just about any (para)military songbook of the period. The song "Wir sind des Geyers schwarzer Haufen" (which had nothing to do with the SS) can be found in the chapter "Wir zogen in das Feld", containing old soldiers' songs.
I've merged your question with an older thread dealing with songbooks. Check Wim's old download link on page 1 and see if the SS songbook by the RuSHA is still available (search for the file "Liedboek PDF - Duits - ̶W̶a̶f̶f̶e̶n̶ SS Liederbuch - Herausgegeven von Rassen- und Siedlungshauptamt"). You'll find "Wir sind des Geyers schwarzer Haufen" there as well, in the chapter "Der Trommler schlägt Parade" (containing marching songs). The song can be also found in numerous other (non-political) songbooks, from 1920s to 2020s.
Cheers,
Ivan