I've had a few vintage guns that had a few pits....looked at some that had lots of pits.
I recall one sweet little English hammer gun...just got it in the mail.
I took the barrels out side and looked to the sky....I saw something then it disappeared I turned and twisted the barrels there it was again....then it disappeared again
I laid the barrels down on the bench and this little cock roach ran out on the table.
Even was told by this English sounding gEnt (that said he was an English gunsmith) that he actually could measure the depth of the pits in the gun he was selling and get back to me....I said "no thanks".
No matter how tempting I try and stay away from guns that have any pits in the barrels....most likely they won't blow up but like was said they are the devil to clean (if not truly impossible to clean) and a gun with pitted barrels might be the devil to sell should you find you can't shoot it well.