Hey all, Just picked this up tonight and hope you all can answer some questions. First How can i tell how old this pistol is. Also i own a Beretta 96 .40 cal. And i can switch slides so i can run the 9mm setup. I was wondering if this can also be done with the sigmas also. is there any other mags that fit this gun. This one only came with only 1 10rd mag and i need more. Any help would be appreciated.