It looks like a wire wheel was used on the bottom base of the barrel, removing it's markings too...

In your first post, you asked about legality of carrying it. Now that it's clear that the serial number was removed there might be legal issues. I'm honestly not sure how they would treat a current owner if a prior owner did the removal. Do you have a receipt that indicated it had no serial number when you purchased it? If not, it might be time to consult someone...

Marc

I agree with Marc on the barrel as well. One thing is for a pre 68 gun to have NO serial number. It may be quite another to have a REMOVED serial number. I would check ATF regs.