Very nice looking plaques for sure. Was this casino ever open, and if so, for how long?
$300 each seems a bit high. Even very unique plaques don't tend to sell for that high unless they are VERY high denominations (which also tend to be rare and also quite large and ornate) , or plaques used in Nevada casinos (Sands/Sahara). I would be interested in one of yours if you decide to lower your price, or might take some plaques or chips in trade