German military or Feuerpolizei helmet 1950s

Description

Had this helmet for a number of years.  Not been able to identify.  Marked: S.W.B. 59   Potentially post-war Bundeswehr parade helmet.
Priced accordingly
Some folks commented that it could be a former Luftschutz helmet repurposed by Bundeswehr after the war.  However, Luftschutz are normally made of metal, while this one is clearly fiberglass.  Postwar luftschutz were also normally white color while this one is factory military grey.
Very interesting.  Once I hear more, I will add to the description.