Classic & Vintage - Simplex Super LJ. Busted?

Hey,
I bought this derailleur of the 'bay without seeing a pic of the back side. When I got it I noticed the little problem by the attachment bolt but it really didn't matter to me at the time because I collect rear derailleurs and had no intention of ever using it. Now I have a Peugeot that needs a derailleur and this one is the only one I have that will fit the Simplex dropout......
So is it usable? I don't really want to use a gold one but I will until I get another one to use if it will work.

http://farm4.static.flickr.com/3046/2879414949_23cc55ac92.jpg

Anyone have a really clean Super LJ (5500 or 6500) laying around? I've got good trade stuff and cash....
Is there any other comparable derailleur out there? I'm a noob to the French stuff....

The problem I see is fixable. What I see is the plate with the tang needs to rotate about 45 degrees counter-clockwise so that it catches the lip on the derailleur body about the 8:30 position. Or has someone filed down that lip? It will take some ingenuity, but can be done.

Or did I miss the problem entirely?

I lifted this pic off of velobase:
http://www.velobase.com/CompImages/RDerailleur/596DB4C8-3AAF-4172-B3A5-0A65261C3581.jpeg
I hope that's OK. Anyways....As you can see the "plate with the tang" on it is supposed to be inline with the shoulder of the derailleur. Mine has been rotated into the shoulder and messed it up a bit.
Question is: Is that going to mess up the performance of the derailleur? What is the plate there for anyways?
CV-6, thanks for your input. I think you are correct in that the plate needs to rotated. But what is going to stop it from rotating again? How did my derailleur end up damaged like this? Maybe someone was ham fisted and tightened it up to much? Point is..... I don't want to make it any worse than it is.

I just went out a played around with my Super LJ and it seems like yours will work fine the way it is. Have you tried it? Mine has a stop to keep it from rotating too far to the rear, but the chain keeps it from ever getting near the stop.

The picture you lifted from Velobase is not an SLJ, it's an SX. They work just the same, the SX just weighs about 40 grams more and gets no respect.

Thanks Dirtdrop.......I haven't tried it yet. So your saying the plate just prevents the derailleur from rotating to far back? I wonder if mine got a good whack that forced it back to far thus damaging it?

Thanks Dirtdrop.......I haven't tried it yet. So your saying the plate just prevents the derailleur from rotating to far back? I wonder if mine got a good whack that forced it back to far thus damaging it?

The plate is the anchor for the spring that tensions the derailleur. Yes, as Dirtdrop says, your derailleur will probably work. Maybe just not as well.

You might be able to mount the derailleur and twist the derailleur body so that the plate drops back into place. It would take some experimentation.