14" Bronze(i think) goldfish

I bought this fish at an estate sale.  I think it is bronze.  There is a little bit of greening on the bottom.  The pictures make it look super shiney but it is just semi-shiney.  It is almost 14 inches.  When you look inside the mouth you can see a seem up the middle and it looks like it was hand done but I dont know a lot about these things so please take that with a grain of salt.  It really is unique and everyone asks about it.  There are marking beneath the tail.  It looks like a M and a small line.  I have attached pictures on the markings.

Good