My local muffler shop buddy removes those stock mufflers left and right for folks who want loud replacements. He just throws the OEM mufflers onto his scrap trailer for recycling. I'd bet it's the same case in Dallas. Maybe find a friendly small time muffler shop and tell him that you're picky and want a stock muffler and get him to contact you next time someone comes in to have one cut off and replaced with louder.