Röhm RG 800

So, I came into possession of a pretty old Röhm RG 800. I got it from a friend in Germany. He claimed it was his father's whilst he was in the German Army. It's been schlagged and the metal's not in very good shape. I am having a lot of difficulty finding any info on his gun online (that's not in Russian, that is). It looks like the current Röhm RG 90 is a very similar model, but I'm not sure. Does anyone have any info on this particular gun? I am trying to do a research paper for a German history seminar. Thanks in advance for any help.

Here's information that's not in Russian. Instead, it's in Czech.
Click on: http://images.google.com/images?hl=e...ed=0CCkQsAQwBA