Thank you gentlemen both for your replies and inputs.  I will try to take a higher resolution photo of the serial numbers to ascertain if it has been restamped or not.  The stock cartouche is veryfaint, so I will try to photograph the cartouche using under different colors of light to see if anything can be brought out (this was suggested to me by a police officer that does forensics).  As for the receiver, the inside looks perfectly uniform and has no discoloring that would be indicitive of a weld.  I even had a licensed gunsmith look at this also and he verified. 
     I know I keep putting theories in the mix (sorry but it is in my nature being in medicine) but a history professor friend of mine at the local community college had an idea since that O'Neill was a wagoner, some of those guys carried their weapons lying across their laps as they drove their wagons.  The receiver could rub against their belt buckle and with the corrosion associated with the tropical conditions, could make it this way.  Also, there is a faint thumbprint that the picture does not bring out that is etched into the metal.  I will try to take a better picture of this as well.  You have both helped alot and I am grateful.