Well, currently there are two 540r guitars for sale. This is one, and the other is a rosewood board. The rosewood one is 1991 and has that horribly custom inlay on the 21st fret, and the dude is asking 3000 Reais on it, compared to 2500 on this one. There is a third radius on sale, but it's actually a 440r and it's 2000 Reais.
I was a bit iffy on the third knob as well, but from what the seller said, it acts as the third knob on a strat to control tone of the pickups separately. Considering the H-S-S config, I don't think that's a terrible idea. I'm still talking to the seller to see how it goes. Worst scenario is that I'd give it a pass, which I hope not, cause I really want to have a Radius. I could wait to buy a JS
someday, but I'm always a bit discouraged about buying signature gear, and a JS1200 is about 9000 Reais here, which is just completely out of acceptable price range for now.
Edit: Also, I forgot to mention that the used market here in Brazil works a little bit different, unfortunately, than in the US. Rare stuff is always priced higher than normal, purely based on the rarity factor. I once saw a RG770 going for more than 1000 dollars and the color was completely faded, and the hardware didn't look good. But since it was a guitar from the very first run of the 770 it ended up selling very high.
Edit2: Correcting some info. Stupid ads