Indeed, the Historic District sign affixed to the building identifies it as the Walls Bank Building while the description below, from the NRHP Nomination Form, notes that it was built in 1920. Research would indicate that the bank was owned by Judge W. L. Walls, later a state prosecutor. A previous bank building owned by Judge Walls housed the First National Bank, which, incidentally, was
robbed on November 1, 1904 by two as yet unidentified men, one of them killing cashier and part owner and founder of the bank, Ira O. Middaugh, during the attempted robbery. A gunfight ensued between the bank robbers, who left without securing any cash, and townspeople as the gunmen fled.
An exhaustive article on the event can be found at the
Cody Archive.
To our knowledge, there were three banks in Cody by 1920, the First National Bank, the Stockgrowers Bank and the Shoshone National Bank, all of which were in place by 1909, at the latest. If the relationship between Judge Walls and the First National Bank continued until 1920, this building would have housed the First National Bank. The 1904 robbery of the First National Bank took place in a building at the same location (the corner of 12th Street [at that time 2nd Street] and Sheridan Avenue), so it's safe to assume that this 1920 building simply replaced the earlier building.
As, due to the nature of the website containing the Wyoming newspaper archives, it's not possible to post a working URL to the news article published by the Cody Enterprise, I've included a screenshot of the front page of the November 3, 1904 issue.
The bank, located in the Walls building, corner of Sheridan avenue and 2nd street, has an outlet on the street from this office and the big man, when be could not enter the office...
From the news article in question
Today the building is home to
Sean DeNamur Designs Fine Jewelry.