new guy with serial number placement question

[INLAND44]

Yes, there was a revision so the serial number could be re-stamped on the front of the sight bridge if the new adjustable sight covered the original one. I don't remember seeing one done that way but obviously they're out there. I think this one was stamped prior to the revision, making it a fairly early sight replacement. Its also possible it was done in the field before the revision was known at that location. Many carbines' serial numbers were not occluded by the new sight which is why the re-stamping is fairly rare.