Here is a post 1870 and pre-1877 cover. The illustrated building was lost in the hours after 8:12 AM, April 18th, 1906, with a new fireproof 8 story (later 10 floor) building reconstructed on the site. While the former did not withstand The Great San Francisco Earthquake and Fire the replacement withstood the 1989 'World Series' Loma Prieta Quake and still stands today:

Sherman & Hyde (From:
https://antiquepianoshop.com/online...herman-hyde/ )
The Sherman & Hyde Piano Company was a part of the most successful music retailer on the West Coast. In about 1870, Leander S. Sherman purchased a large music retail store in San Francisco from a gentleman by the name of A. A. Rosenberg. Mr. Sherman was joined shortly thereafter by F. A. Hyde, forming "The Sherman & Hyde Company". During the early years, the firm was primarily a retailer and distributor of sheet music and musical instruments, including pianos and organs. There is evidence of a limited number of instruments being manufactured and sold under the "Sherman & Hyde" brand name, but they are very rare today.
In 1876, E. C. Clay joined the firm and the name of the firm was changed to "Sherman & Clay Company". During the early 20th Century pianos sold under the "Sherman & Clay" label were manufactured by The Haddorff Piano Company. Sherman & Clay went on to be one of the largest and most successful musical instrument retailers on the West Coast, and they are still one of the largest and most prestigious music store chains in America today.
A wonderful history of Sherman and Clay (glossing over the Sherman and Hyde name the first seven years) filled with explanations of the times and a fine read can be found here:
http://www.shermanclay.com/The city of address, Sutter Creek, is named after John Sutter who moved there for a while after his discovery of gold at his mill near Coloma which started the California Gold Rush in 1848. The PO was established in 1852 with the area becoming a town in 1854, a town which remains today.