[ap1169]

I just purchased a Mauser Luger in a Semi Phosphate finish with a box with SA in it on the slide and a circle with a triangle and n up side down T? Does anyone know what these markings mean? Is this a rare pistol? Only numbers on the trigger, barrel and slide, no other numbers on this firearm? Thank you very much for your help. Please email me for pictures. I don't know how to upload them from photos. Robert