A scene where a man holds up a silver dollar shows it to be a "Peace Dollar", a design used from 1921 - 1935. A more appropriate design for this time period would likely be the "Morgan Dollar", which was used from 1878 - 1904, and 1921.
The Big Valley was set from 1884 to 1888. In this episode, two characters are running for US Senate and are campaigning for the votes of normal citizens. Since this election would have been held before ratification of the Seventeenth Amendment in 1913, senators would have been elected by the legislature and there would have been little reason for candidates to be addressing the public.