If the front V8 engine brackets are riveted to the cross member than it was a factory V8, (if bolted it's a conversion and was born a 6-cylinder) and the Cab tag serial number would start with a "V" (not stamped on the frame)...
So the trucks chassis was either born V56S023812 as a V8 truck or 56S023812 as a 6-cylinder...
V = V8
6B = 2 ton 154" wheel base
56 = Year
S = St Louis
023812 = Unit number atarting with 001001
Your Cab 3A57511xxx breaks down as follows...
3A = 1/2 ton short step side
57 = year
5 is a typo...bet it was "S" = St Louis
11xxx = Unit number starting with 100001
Sending you a PM
Mike B
