The rounded cab floor was postwar-only, as was the black handrail version. The 1946 version with silver handrails and straight cab floor was probably leftover prewar production.
IIRC, the black handrail was 1946 only (I have one knocking about somewheres with the club stuff).
Did Lionel offer plastic/bakelite tender shells prewar, or was that a postwar innovation?
Mitch