Yes, that what it looks like to me.
I'm thinking the same thing as well with the color coding - from looking at other photos, it looks like Junkers went predominantly with brown, with few exceptions.
As for the location of the throttles, I'm thinking that the taller ones are the throttles, and the shorter ones are prop RPM levers. You can just make out one of them in the color photo, and then you can see it really well in the black and white photo.
My conclusion at this point is that, since we know the throttles were brown on the A-1 series (based on the restored example, WerkNummer 088119), they were also brown on the A-4 series and other variants. Working off of that assumption, since the prop and RPM levers in the USAF's D-1 plane are all the same shade, they then should all be brown.