It looks like it was (originally) two pieces, but over time, as plumbing likes to do, it corroded to the point that it became one. But, it's irrelevant now. It is now in at least seven pieces :B
That right there is why I hate plumbing. And plumbers know that there are millions of people like me who hate plumbing, and will pay any price to have someone else fix our broken plumbing. Which is why they charge more than doctors and lawyers on an hourly basis.
May your plumbing repair require no more than two trips to the hardware store. :B
:):)