A couple notes for you here.
I have it from Sheldon Brown, that the correct pronunciation for the Raleigh bicycle Superbe, is as Charles Wahl suggests. Now the Japanese may not pronounce it the same as the folks at Raleigh, but I'd go with that until someone corrects me.
I don't think you can go by what I paid. Mine was $75.00 from CraigsList. The seller was kind of out in the sticks, and he didn't have the right rear derailleur for it on the bike (I brought him a proper MTB derailleur to put on his wife's bike so I could get the Dura Ace RD.
He had no idea what the model of bike was - and neither did I at that point. He thought, and I concurred then, that the primary value in the bike was the stuff on it. The bike had already been refinished, and was not refinished very well. There was only some light surface rust on the fork chrome, but whoever painted it didn't even bother to remove the bottom bracket first.
I got mine re-re-painted by Dr. Deltron (I won his contest, and it's a lovely deep purple candy now). I'm building it up with up 9 speed cassette. I've put 126mm axles on bikes spaced for 120mm before with no issues at all. Going from 126 to 130 is no big deal.
Go see this guy before it's gone. See if you can test ride it. I think $300 is kind of high. I thnk the one I bought was probably worth about double what a paid. This one - $225 - $250 would sound like a fair deal if it's pretty much ready to ride. Maybe a little more if it's in very nice shape. Bear in mind that I'm used to Harrisburg prices - which aren't Philly prices. He might well get $300.00 for it there.
Good luck. I'm about to sell off my Bob Jackson because I'm replacing it with the 760.