Peculiar HP-41CV with RS 620-480 Logo

[jbmorg]

Hello all,

I found this strange HP 41CV. I can turn it on, but after that it behaves strangely, I can't really do much with it.

But there is something very odd about it. In that little strip at the bottom of the keyboard that usually says only HP-41CV, this one says RS 620-480 HP-41CV.

Here is a picture:

http://imgur.com/a/G73hd

Does anyone have any idea what this is? How do I get it to operate correctly?