have come into possesion for these to pistols can anyone shed anylight on there age value etc they are both stamped diana made in great britain. The mod 2 is in good condition with nice bluing the mod4 has lost its rear sight and is pock marked with rust but is still showing most of its original finnish they are in working order all feedback gratefully accepted C.J googled them and found out some stuff on model 2 but the mod 4 stamped IV seems to be a mystery HELP!