Hello Mikee, execution seems somehow crude to me. But the stamping says "apprenticeship workshop" (of the city Wuppertal) therefore it could be a workpiece on which the apprentices did learn how to handle certain tools. There were funny things (see my letter opener of a flyer´s technical school and the proper, period postcard) and it is easily possible that your letter opener was made during 33-45, but we will never know for sure until any period documentations (like eg. a postcard or another photographic documentation) does surface.
Regards,