The Bassman 135 has an ultra linear output stage, which is probably workable for bass. The UL output stage sounds very good clean and gives it a fairly raucous overdriven sound rather than a "smooth" distortion more common with other output stage designs. The claimed output gain is due to this circuit change, but it is highly unlikely to put out 135 wrms, probably more like the usual 100wrms or so from 4 6l6gc's.
$395 is a fair price, but no steal. I bought a drip face dual showman (same circuit as blackface) last year for $450, and it is a much more musical amp IMHO.
A bunch of gear