I am hoping you guys can help me out. I am trying to identify a particular shotgun. I work as an independent insurance adjuster for the General Casualty Insurance Company. I have an insured who has filed a claim that their shotgun was stolen during a robbery at their home. The insured presented me with a photo and all the details that she knows about it. According to her, it is a 16-gauge shotgun, model # 1152. She doesn't know the name of the company that makes it though or where she bought it from. The insured told me that the gun is an antique and worth quite a lot of money. So here I am stuck with identifying and appraising this shotgun so the insured can be paid what it's worth. I am wondering if you guys can help. I have included the picture below that the insured supplied me with.
Thanks in advance.

Thanks in advance.