SL 1000 Silver Coil Dome?

stubby

I just bought this tweet off ebay. I was under the impression that the 1000 was the oldest model Polk made. The grey one with the diagonal windings. This one is the Silver Coil Dome with horizontal windings. It is marked SL 1000. I thought these were all SL 2000's. Is there any difference between the two? The guy had a picture with the listing and I thought he may have misread the back. I know mine take the Silver Coil Dome but mine are 2000's. Hopefully they are the same, just named different. I just bought it for a spare, but.....
Stubby