This pen is interesting. The contents of the Wirt factory were bought by a collector and sold to another. My Eagle Correspondent pen was found in the pens left over at the Wirt factory. It is pristine and appears to have never been used. And there is an odd flat piece of hard rubber inside like a version of the paddle feed that does not really belong there.
Later I acquired a Wirt pen using the full length rear end joint set up, similar to the Eagle Correspondent pen.
The Wirt pen has a number of other unusual features. First, the section has extra knurled bands. It attaches almost in reverse with the “male” portion of the threads on the barrel. Second, it has a small cap like a straight cap, but it is threaded. Thirdly, it has a tubular over and under feed, likely patent 358,525 March 1, 1887, but this feed is not seen on other production Wirt pens.