lionheartguru
to find out if it a suppressed pistol or not, just put some wd40 on the end of the barrel and leave it to sock for 30 min. try to unscrew the end part if it is threaded then it should come loose. if it comes loose then pull out the top tube, and if it comes out you will see numbers of bafflers etc and you should see a second barrel with holes in it. if that's the case, keep it, stay shut, or sell at higher rate and do check your fathers license.
if not, its been a nice exercise
other interesting thing is that you have 12rd mad, most hi standard came with 10rd.
if the serial number is between 110074 to 130040, may be and i say may be a suppressed item.