It's funny how hard it is to find any official info on ANY Iceman bass.
I've found hundreds of Ibanez catalogs online and even my 2004 Korean ICB200--which was made in fairly large quantities compared to your ICB500--never seems to show up.
We can look at a few things to determine a fair asking price, but in the end you'll probably never get as much as it's truly worth.
Starting with my ICB200, they regularly go for $200-300 (I paid 2) and it's an inferior instrument due to the bolt-on neck, mini-humbuckers, and lack of body binding.
On the other hand, mine has block inlays and the antique violin-type finish lets you see the quality of the mahogany body and the fact that it's only two pieces. Black is 'metal' but boring.
The ICB200's gold hardware is typical in that it's carat level is so low that it actually tarnishes easier than chrome, so the black finish on yours is superior as is the high-mass design of the bridge.
The difference between Japan and Korea manufacture is minor in realistic terms, in my opinion--they are both very high quality.
My gut tells me that your bass SHOULD be worth $500+ on the used market, but I don't have much to back that up and the matter is settled by what someone will pay and what you will accept.
That's what I would offer you as a starting point, and IF I had that $$$ right now we would be negotiating. It's a great example of a rare and desirable Ibanez.
Sadly, you have to go back a few more years to command "Vintage" prices and fanboy status.
My 1977 Artist 2619 guitar has more than tripled in the prices I've been offered since I bought it new, despite ALL of the hardware being replaced 3 times due to the aforementioned cheap gold plating. Grover and Gibson have rotted just as badly as the original parts, yet people just seem to lust after my now frankenstein guitar.
Some models just don't do as well as others.
Ibanez#588/8 String#43/Grumpy Amps#78