Welcome to the thread, SoCalPaul, and it's great to see your images. The first shop was at 8684 W Pico. There appear to be a few remnants of the corner's time as a flower depot.
Google Street View
Google Street View
Google Street View
As for the Nose Gay location--there were also a number of Roberts Public Markets quite a distance from downtown L.A. in directions other than west (the company was based in Santa Monica). I really can't make out the address on the Nose Gay. But if it's 11-thousand something... there was a Roberts once way down at 11014 S. Figueroa. The street view today shows two buildings reminiscent of the Nose Gay and the Roberts market, but not the same. Could your grandfather have had a shop all the way down on 110th Street?
In 1940, Roberts stores in the Santa Monica & West LA area included 312 (an early Paul Williams design--more on that later), 1505, and 1915 Wilshire in SM, 11841 Wilshire in BH, and 11526 SM Blvd in West LA. Also in SM at 420 Broadway, 2716 Main, and 1311 Montana. Some of these buildings still stand, but I didn't see any that corresponded to the one in your pic.
P.S.-- A little more history on the Roberts chain:
"Fred Roberts was the founder of Roberts Public Market, a Santa Monica based chain of grocery and liquor stores started in the late 1920s. (From 1936 through 1948 the Roberts Public Market rented space in the Williams designed Edwin Building.) A successful entrepreneur, Roberts would expand his markets to 19 stores in Santa Monica, Venice, and throughout Los Angeles. He sold the chain to Fitzsimmons Stores in 1949." (
Los Angeles Times, October 21, 1949).