yeah Interarms is Walther which is ownd by S&W (Smith and Wesson) theres many diff models of the ppk, the first was introduced in 1931, ppk stands for Polizei Pistole Kriminal, the model ppks that your dad has i believe is the some what old one, its the same model that Bond uses lol Again its a great gun and should be worth some money, hold on to it :thumbup