It's got the same lugs as the Moto (somebody who knows Nervex should tell us what those are called) and some other details jibe, too. I still say examine the remains of the decal for any mention of 531. For $26 you have already scored a bargain, but it *may* get even better...BTW: research says that Astra was a private label made by Motobecane for an importer in Yakima, WA