GMAT Sentence Correction (SC) | Re: Many of the earliest known images of Hindu deities in India

Good explanation

I am confused,
why can't we just regard the "fashioned either from the ...." as an adverbial modifier which modifies "known imagines " ?
Is the sentence make a sense If we reorganize it into "fashioned either from the spotted sandstone of Mathura or Gandharan grey schist, many of the earliest known images of Hindu deities in India date from the time of the Kushan Empire. "

Thx verrrrrry much