The San Francisco public library historical photo collection has one single photo of the Mars hotel at 192 4th street at the corner of 4th and Howard, where the Moscone Center is today. 3rd and 4th streets near Mission and Howard was a low income area in the 60's and 70's similar to 6th street today and was demolished to make way for the Moscone Center in the 80's
This photo is dated November 14, 1963, at the corner of 4th and Howard - S. F. News-Call Bulletin photo by Eddie Murphy.
The Mars Hotel was immortalized in the 1974 Grateful Dead album of the same name.
this is 4th and Howard today, now called Moscone West
these photos provided by people at The Jerry Site with some from the original album
The album itself was recorded only one block away at the CBS/Automatt at 829 Folsom. David Rubinson, who owned the Automatt, was the second manager for Moby Grape and produced a ton of bands. More history of the Automatt. History of 827 Folsom - CBS studios and a another blog with history
this is the original Coast recorders at 827 Folsom in 1968, later to become Columbia/CBS/Automatt. The building was torn down long ago and is now condos
from the book, If These Halls Could Talk, A Journey through San Francisco recording studios ((Amazon)
Coast recorders is still around, but now located in the Mission