they are ww2 era as are the luftwaffe issue knives
as for books fred stephens one is a good start. deutsche kampfmesser by eugen von halasz. (isbn no.3-931533-33-6)is superb but is in german it covers ww1 ww2 and post war.also german fighting knives 1914-1945 by gordon a hughes(isbn no.1-871498-15-5)
hope this helps
Sean


Regards Sean