Yes, each of the Yanmar engines in these Deere tractors (the 322, the 332 and the 430) have a different part number for the muffler and they are not the same assembly. As noted above, the 430 tractor takes a uniquely shaped/bracketed muffler to fit correctly. While the 322 and 332 units might mechanically mount on the opposite engine type -- they have much different exit pipe sizes and likely very different back pressures so their functions are not equivalent.
Exhaust system designs on small engines can be critical for peak performance -- hence all the engineering invested in those systems that are "tuned" for a particular competition/RPM range, etc. I doubt that the Yanmar exhausts are anywhere near that critical, but the fact that the part numbers are unique to each model speaks to some reasoning being in place to choose to have different parts of lower production volumes over a "one size fits all" approach.
Chuck