This is not a typical Old Town serial number format so some pictures of these numbers and the interior of the boat would help. The usual format is a four to six digit serial number without any leading zeros followed by a two digit number that corresponds to the length in feet. See
http://forums.wcha.org/showthread.php?791 for some examples. Can you also confirm the extreme overall length of your square stern? The records for numbers 125152 and 5152 are attached below in case those happen to match but this doesn't seem likely.
Benson