While not exactly a western movie, this inaccuracy with a player
piano in a old west saloon appeared in an original Star Trek episode,
"Spectre of the Gun," originally aired on October 25, 1968.  A brief
summary of the episode --

The Enterprise, under the command of Captain James T. Kirk, is
instructed to make peaceful contact with the Melkotians, the mysterious
alien inhabitants of Theta Kiokis II, but is warned away by a strange
space buoy that orders it not to proceed to the Melkotians' planet.

Ignoring the warning, Kirk takes the Enterprise to the planet anyway.
Captain Kirk assembles a landing party consisting of himself, his first
officer Mr. Spock, chief engineer Mr. Scott, chief medical officer Dr.
McCoy, and navigator Checkov and beams down to the surface of the planet
to make contact.  The Melkotians are angered by this and imprison the
team in a psychic illusion that takes the form of the town of Tombstone
AZ on Earth upon the historic date October 26, 1881.  Kirk and his
companions quickly realize they are now impromptu characters in a
bizarre reenactment of the legendary Gunfight at the OK Corral, with
them on the loosing side.

The setting for the town is actually downloaded from Kirk's mind, but
the Melkotians only had fragments of memories to work with; therefore
the illusion has a surreal incompleteness to it -- buildings are
obvious facades, windows and pictures appear to float in mid-air,
doors open to nowhere, etc.

In the saloon is a player piano, with the spoolbox doors open clearly
showing the roll -- a machine that is completely out of date with the
timeline.  The landing party also sees their equipment is changed;
weapons turned into pistols, communicators and tricorders are missing,
and there is no longer a way to make contact with the Enterprise.

Star Trek creator Gene Roddenberry was a noted stickler for accuracy,
so it is very difficult to determine that he was aware that the player
piano was incorrect for the date 1881, or it was a deliberate "mistake"
attributed to the fragmented information of the Melkotian aliens.

Andy Taylor