My elderly mother has asked me to help her sell a few things and one of them is this aqua colored dolphin footed bowl. I’ve done some research and think it might be Heisey but there is no Heisey mark. I have read that it is not unusual for the mark to be missing? Is this true? My main issue is trying to price this item as I can’t find any other Heisey items in this color. I would greatly appreciate any advice or expertise on this item as I want to get my Mom a fair value for her things. Thank you in advance.