The only information I have on this comes from an Ebay sale in Australia. It is said to be a limited edition possibly of
180 units. These specs are from the sale:
The serial number: KZ0K083
Guitar was made in Japan on December 4th, 1984
Body Mahogany with Maple Top
Neck Maple set neck
Fretboard Rosewood with small shaped inlays
Number of Frets: 24
Pickups: 2 Humbucking
Controls: 2 Volume , 2 Tone , 3-way pickup selector , Push-pull coil tap SW × 2
Hardware: Gold Plate
Weight: 3.8 kg.
Special Features: Locking nut Yamaha Rockin’Magic Tremolo (Floyd Rose type)
I cannot find any other details anywhere except for the occasional reference in a search but nothing else.
The headstock style is similar to the second series but the SF script is different
The natural successor to the SF is the SFX range which look very similar but are signature models.
They are in my Rare and Unusual Yamaha section here: SFX
There is also a short lived 2002 Exart NSF New Superflighter guitar a reissue of the SF 1000 again the magic number of only 180 made is frequently mentioned.