Napco Three Horse Head Planter ???

I found this planter at my local thrift store. I thought it looked old and might be a collectible. I inspected the bottom and saw that it had a number (S221) under the glaze. I started to search the internet and was able to find out that it was a Napco planter. So I typed in Napco S221 and only one article came up. An ebay listing from 2008. This is the only thing I can find on this planter. Any information and/or what it might be worth, if anything, would greatly be appreciated. Thanks!