I just purchased a New haven 600 shotgun which I know is the same shotgun as a mossberg 500 and I am having trouble locating the serial number, does anyone know where I can look? I have completely disassembled and cleaned the shotgun but haven't found any numbers on it. I am thinking this shotgun was made pre 1968 hence the lack of the serial number. i think I did pretty good I purchased it for $125 FTF, it was painted a flat black with what I am guessing is barbecue paint and the wood stock was painted green with flecks in it
I have a department store (western field) Mossberg 500 that was made pre 68, the SN on it is on the left side of the receiver above the trigger guard on the flat.(the side showing up in your pic.) if it isn't there or on the bottom in front of the loading port then it must not have had one.
125 is a good deal, that is how much mine was (before taxes and background check