"They Drive by Night" - Sterling Truck?

I found another picture of a truck mentioned in an earlier post about the Bogart / Raft movie, "THEY DIVE BY NIGHT".

When I looked closely at this picture, I noticed what appears to be another set of wheels behind the rear duals. I checked other pictures, and the only one that shows that this might have been the way the truck was set up, is the picture used in the earlier post.



If you look closely behind the left rear dual, you can just make out the shadow of another tire. I wonder if this is how the truck was set up? Anyone know?

UPDATE: ---- Recently the model used in the accident scene was sold at auction -- sale price was $25,300. Below is a picture from the sale --

And here is some info I found on the model before the sale --