Lots of stuff flying around here!
Phil's EB-3 had some mods done to it, primarily the pickups were swapped out for BiSonics, the tailpiece was added, and the electronics were updated. Whether or not there were preamps added is a point of debate, as Dan Schwartz, who actually had the bass in his hands for a minute, and Rick Turner both say it was a passive bass. And, of course, the fantastic paint job!
The biggest reason Phil's EB-3 sounded nothing like the players or instruments referenced above is largely due to the pickups (I'm not a fan of the stock tone). I think he also probably had a stereo output on the bass, with each pickup getting its own amp/speaker chain, but that's speculation on my part.
As far as calling it an SG bass, well, that's what lots of people on the street called it!