I'm not sure Ray understood the question, or else I don't.  I took it as did early (how early) DS box cars have (a) single fascia boards with a horizontal bottom edge, or (b) two fascia boards per end such that their bottom edges paralleled the roof pitch?  And the answer is yes, plenty of examples of both.

But I don't quite understand quite what Chuck is looking for.  A prototype to closely match the model?  If so, there are a number of other spotting features that should be considered.

In the FWIW department, early (truss-rod) Swift reefers sported both styles of end fascias, even within the same car series.  I don't think it was a particularly rigid design element in cars of the time.
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Dave Parker
Swall Meadows, CA