It's a great harp amp- My favorite. but don't tell anyone else. Prices have been rising on what's still a bargain, - if you compare it to the tweed Fender's of the same era. The circuit is almost identical to the Fender TV Front Deluxe.
I use mine almost weekly at a nearby jam. The jam is electric- with a drummer, but not too loud. The GA6 does the job without a problem and doesn't need to be mic'd into the PA. It has very little clean headroom and breaks up at relatively low volume, - so it's not bad as a practice amp at home too.
An amp that old my need work however if it hasn't been serviced. Check that the speaker is original. Ask if the it's had a 'cap job' - which may be nec. if it hasn't been done. Does it have a three prong cord? - Also recommended.
FYI The black one on the FB harp gear page does not have the original speaker and was painted over. They are ugly to begin with so the paint job may not matter - but the speaker does.
Gibson's are not quite as easy to work on as Fenders because they are true 'point to point' wired. That should not be a problem for a good tech however.
Who's offering it? What price are they asking? ---------- Bone's music videos
I'm not sure who owns it. I was told by a friend in an email that the owner thought a harp player may be interested in it. So I don't know anything about it.