Buttons ''could'' be wartime buttons but they also used them after the war. No markings on those, same as the shirt.. could also been used after the war.
If I had this shirt I would replace the buttons by the orginal silver ones.. It will look much prettier!
Buttons look like DAF, I don't think this a problem at all, I've seen HJ uniforms with these buttons before. From the photos they appear to have been on the uniform for a long time. I think it's good IMO.
Comment