.
Thanks
Hoss. That explains the huge Chevron sign on the roof because 1727 N. Spring is the old Standard Oil Company Sales Office
. (built in 1914)

gsv
... (as most of you know
, we have visited this building in the past)
SOC
(Standard Oil Company) is engraved in the attractive ornament above the front entrance.
(circled below)

laconservancy
I just read that the building used to have marble on the exterior but I haven't been able to locate a photograph of the building when it was the Standard Oil Company Sales Office.
Here is a close-up. (someone has tried to patch it up a bit)
GW first pointed out the SOC in 2012.
And if you go around to the back of the building (on Aurora Street) you can see the faded remnants
(ghost sign) of the Standard Oil Company.

gsv
It's interesting to me that the right (north) side of the building is at an odd angle to the rest of the building as if it were built on.
And lastly, I checked the roof to see if there were any braces or markings to show where the huge Chevron was anchored to the building.

google_earth
There's nothing -sign related- visible.
And here's one last look at the 1940s negative with the marvelous roof-top sign.

ebay / detail
An earlier post on 1727 N. Spring Street by 3940dxr
, here
.