Most manufacturers advertising a specific muffler for a model vehicle usually sell it as part of a full exhaust system. The other two companies I listed (Aero Turbine, Aero Flow) also sell mufflers that'll fit your truck they can be found at Midas Muffler shops.
Almost any muffler will fit your truck, mufflers are pretty much universal. What fits your truck is a 2" inlet, 2" outlet. Configuration, i.e inlet and outlet at opposite ends or the same ends, length, and # chambers depend on how you want to run the pipes.
I'm like Jaime I buy the muffler then get with a reputable exhaust shop to design how It should run.
When talking OEM replacement performance mufflers you'll probably have a hard time finding one to fit right in the stock spot. Oem mufflers are normally very long and big around, they take-up a lot of space. Most replacement mufflers are shorter and smaller around. Unless you use the OEM muffler specific to your truck you'll have to have some pipe work done also.