A picture of William Penn's cabin is here: It has been relocated from Penn(sboro) to Everton
http://www.dadecountymissouri.20m.com/photo4.html
From the History of Dade County, 1917 Pioneer Press
FORMATIVE ACT Dade County was organized in
accordance with an act of the General Assembly of the
State of Missouri, approved January 29, 1841, and an
act supplemental thereto, approved February 15, 1841.
That part of the first act relating to the organization of
this county, reads as follows: ...
Section 12. The circuit and county courts of said
county shall be held at the dwelling house of William
Penn, in said county, until the permanent seat of justice
of said county is established, or the county court shall
otherwise direct.
In accordance with the foregoing laws, Gov. Thomas
Reynolds appointed and commissioned Nelson McDowell,
William Penn and David Hunter as justices of the county
court, and Asa G. Smith as sheriff of the county. In
further compliance with the law, these justices met on
the first Monday of March, 1841, at the residence of Will-
iam Penn (on Pennsylvania Prairie), and then and there
organized their court, and appointed Joseph Allen as
clerk, and thus completed the organization of Dade
County. It was contemplated by the prime movers for
the organization of the county that the seat should be
located on Pennsylvania Prairie; but the clause in ttie sup-
plemental act requiring the seat of justice to be located
within four miles of the center of the county defeated
their project.
...in the spring of 1837, the
McMillen family settled on Limestone Creek about a
mile and a half below what is now South Greenfield; and
at this same time the Penn family settled on what is now
Pennsylvania Prairie...
COUNTY OFFICERS.
County Court Justices and Judges Nelson McDowell,
1841-45 ; William Penn and David Hunter, 1841-42...
So now you know the story of the three. I'm not sure of the veracity of the cane being William Penn's. It may be a token manufactured to celebrate some important anniversery in the history of Pennsboro or Dade County but the names are right and make sense.
The History of Dade County is here for free reading and download:
http://www.archive.org/stream/historyofdadecou00greeiala/historyofdadecou00greeiala_djvu.txt
John R