Yasushi Nirasawa Resin Mold

I believe this is a Yasushi Nirasawa unpainted resin mold. I have not been able to get this authenticated and I know pretty much nothing about it except what I have seen via google search. It was found during a storage unit purchase and the seller had no idea what it was. They measure approximately 5" x 2". Any information would be greatly appreciated such as price and/or name! Thank you!