William
Details of what it was found on and where it was stamped would help. I do not recall seeing a "Starburst C mark" I have observed sunburst K, S, B, D, and L (Weimar Lugers, page 2). These are Weimar-Early Nazi marks. Also, Eagle: K, F, C, and L stamps were used during the Nazi Era (Third Reich Lugers, page 1).
Jan