Final follow up in case someone runs into this in the future, I ended up ordering a 13006 non stainless muffler for 135.00 plus shipping of 18.00. Cheaper than the 220.00 stainless 13008 model that had 40.00 dollar shipping. Don't remember the company name, but out of Elkhardt In. Hydronicheatingwarehouse.com. 866-895-4556
Note I could not simply put the part number into their site and order it, I had to actually get a person at one of their extensions to complete the order.
Hopefully no one else will need a new muffler, but if so this may be helpful.