Looks like a really neat piece - I know nothing of such an item's value, but I would likely be a bidder... A question - are you quite sure the counters are elephant ivory? Some of the staining and chips that I note suggest to me that this may be unlikely. If you are unfamiliar with ivory, you SHOULD be able to find areas where the grain of the ivory looks like it is cross-hatched or has a 'turned' or 'machined' appearance. That is a reliable indicator of elephant ivory vs bone or other similar materials.