I can comment on this bass, since I am the original owner.
It was my only bass for about 15 years. It was purchased from Music Strings and Things on Woodward in Royal Oak in 1976. I had it defretted by Fiddlers Music in Detroit in 1977. It was refretted by Elderly Instruments in 1987. The Ebony board was unmarked during fretless play, because I used D’Addario Half Rounds. Elderly did a superb job on the fretwork.
If the gig bag is the XL I used and sold it with, then it’s a Cordura RB bag.
S/N is indeed close to the 183 already mentioned. I don’t want to say any more than that, because I’m not the seller.
The koa core gives the bass a somewhat unique voice, being a bit more taut and tenor than the more standard mahogany. The neck is also a bit unusual having walnut and birch strips in it.
It is a very nice sounding instrument with great projection. Hope it finds a great new home.