fronobulax

Two pickup basses (SF II) were produced in all eras. One pickup basses (SF I) were produced in all eras except the 90's reissues.

SF IIs all had the pickups in the same locations, almost flush against the neck and just above the bridge.

SF Is had the pickup in one of two locations. A location by the bridge (the "sweet spot") was used in the Early, GSR and Newark Street eras. A location by the neck was used in the Early, Vintage and '70's eras. The "sweet spot" location in the Early era predates the neck location.

The neck location was the same on a SF I and II but the "sweet spot" is slightly closer to the neck than the bridge position of a SF II.

There is an emerging hypothesis that some SF IIs started out as a sweet spot SF I and had a neck PU added. If it is true then it is worthy of its own post.