The 444 and 462 are serial number ranges of the guns. Ithaca changed the appearance of the NID's both metal and wood between these serial number ranges of 444,000 and 462,000. The later guns did not have indicators and substituted border line engraving for the dogs on the sides of the receivers. The stock configuration was also changed with the later guns having better dimensions/checkering, in my opinion, then the earlier guns. Hope this helps.

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