I've never seen one welded before, I have seen them where they are cut and the end double drilled to use a "G" style nozzle, this thing flowed pretty well, the reason they did it is because they wanted to run a 1/2 snoot and already had thier "C" bowl Extrude honed and didn't want to spend the money again (would have had to buy the "G" bowl and had it honed).
BTW you can't tell it was modified...
Extrude honing the bowls makes them have a lot less pressure drop across the stator and increases overall performance, the only thing you need to do is cap off the inlet side of the vanes and finish those off by hand so they dont get distorted.
Extrude honing, BTW is a cool process that uses an abrasive putty (in varying grits) that is hydraulically pressed through the bowl, cleaning and smoothing in the process, we did about 10 of these 8 years ago, but have not heard of many people doing it lately.
Also IMO the "G's" don't flow any better than a "C" but they have nozzle adjustability...