Hi gypsyviolin,
By searching through the Registry for SB-2, ebony board and 'fretless' as another keyword, I find 13 registered instrument on a total of 346 registered SB-2's. There are also 2 registered fretless SB's with a rosewood board. So assuming the registered instruments are a random sample of what is out there, about 4.3% of the SB-2 are fretless. Doing the same little test for L-1000's, you'll find 34 out of 438 (or about 7.5%), 36 out of 643fretless L-2000 (or about 5.5%), etc. So all numbers are within a factor of 2. To claim the number of fretless basses for any G&L model is less than 10% is a fairly safe bet to make.
For value, I would have to consult what the Vintage Guitar 2011 Price Guide is listing the SB-2 for. I will look up that number this evening.
Hope this helps,
- Jos
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