Out of curiosity, I did a search and found this piece among The National Register of Historic Places, which mentions Margo's Saloon. :)
Site 390 - 509 E. Main Street. Ca. 1885. Commercial. Contributing
This is a ca. 1885 one-part brick commercial block with a two-story dwelling section at the rear west side. It has
fixed windows and double wood doors with glazing. Windows and doors have been altered and the brick painted but the
building retains its form and materials.
A good local example of a one-part commercial block, this building displays corbelled brickwork in its parapet.
Many contemporaneous buildings in the community exhibit similar architectural embellishment. This building is also
noteworthy because it retains much of its historic character and integrity. The building appears as a General Store on the 1894 Sanborn map and is attributed to Juan Margo. It is also known as the Francisco Margo Drug Store, but is better remembered as the infamous Margo Saloon where Gregorio Duffy was shot in the alley as he exited the back door in the aftermath of a contested election in 1907. The building possesses local historic significance and, although features have been altered, it is considered Medium to High priority property that Contributes to the historic district. This is the website address: http://www.nps.gov/nr/feature/hispanic/2009/05000656-text.pd...