My best method is to get the OE part number , then just use it in a goog search , you're gonna get hits from someone close to you, or someway to order the part. As GM was the originator, all the aftermarket suppliers referenced that part and then added there own number. The 3691500 goog search, hit on Napa, O'Reilly, Chevy dealers, and others.
Yeah you could walk in some stores and ask , and you get the blank stare. But through the magic of digital number crunching linked data base you can get what you want.