Anybody familiar with 1983-1985 IronHead Sportster XLS Roadster serial number anomalies, weirdness?

I am looking at buying a supposedly one-owner XLS Roadster, and the numbers on the frame and title match exactly...

But the numbers on the case seem to be weird, they don't match frame or title, but the last six characters do...
They do not look to have been altered and they do look like they came from the factory that way...

can anybody share some light on what appears to be unique to the 82-85 XLS Roadsters?

thanks in advance.

 

Can you post pics of these numbers? The case VIN is an abbreviated version, same as frame version but with some characters omitted. There is nothing about the Roadster model VIN that is different except the model code embedded in the VIN.