This seemed familiar, so I dug a little--it was mentioned in
this 2012 post, though the picture (which might be the same as yours, Hoss, is missing).
Welton Becket was at 5657 Wilshire, a building we've seen before. It's confusing because the caption to the image says "from the sixth floor of the Prudential Building"--but this wasn't the familiar tall landmark Prudential Building we're all familiar with--it was up the street at 5757--but 5657 did have Prudential offices in it, according to the 56CD. Below is a pic of 5657 from your own post
33294 (2016). The LAPL picture below that is one from a 2011
post of mine.
It's really only 5 floors--I guess poor Vandenburgh jumped off the roof.
LAT Feb 27, 1958