Significance of 2nd Serial # Tag?

[HoveringHMMWV]

Does anyone know the significance of a 2nd tag with serial number stamped on it and is usually riveted adjacent to the data plate on the driver's side B pillar? I've only seen it remaining on a few trucks. Is it placed there originally by AMG or during an IROAN or other maintenance?
Thnx in advance.

 

[Action]

A reseller in KY does that with the new state issued VIN tag.

I just looked on epay for a pic of one of his to compare. He has trucks listed there for sale almost every week, but they never show in the COMPLETED or SOLD selection. Maybe using epay to advertise, then pulls it and sells outside to avoid fees? I don't know how vehicle fees go on there.

 

[HoveringHMMWV]

These were/are on GovPlanet trucks. Plus, the serial numbers appear to match what is on the data plate.

 

[GuntherRommel]

My dmv asked to see a second location with the serial number when doing the vin inspection, maybe this is why? Luckly it had 2 spots already