These are rim fire guns, if there was no round in the chamber and the gun was dry fired the pin could strike the rim of the chamber when the pin flys out of the frame.
However on MY gun the pins are clear of the rim when extended out of the frame.
To check yours, lower the hammer on each pin with the barrels swung open, the close the barrels slowly and see if they make contact with either pin.
My x-ray vision isn't working right now, I can't see the pin when I close it. Either way it wouldn't matter if the chamber was dented.... The firing pin puts a good dent in the rim of the round but doesn't fire, when I put the same round in the lower chamber, it fires.A
here's what to look for next. I found damage on mine that could explain why my bottom pin is not extending as far. Looks like someone pulled the trigger with the safety engaged and the rocking part that hits the different pins has a dent in it.