You can still get a ton of parts for the blueline machines from sapphire....but something like that... I would take off and see if a auto parts place can match it...and if not..a muffler shop would be where I would go...
Tractor Supply has several on the shelf that you can buy, I have looked at my muffler on my PC legend and I swear it looks just like the ones they have. https://www.tractorsupply.com/tsc/search/muffler