my - guess = 1949?

If parts are same as original:

Fuel tank inside the cab, (so, later than 1948)
no side vent window, (so earlier than 1951)
turn down outside door handle (earlier than 1952),
two emblems on side of hood (earlier than late 1949).

Tim
1954Advance-Design.com
1954 3106 Carryall Suburban
1954 3104 5-window pickup w/Hydra-Matic
The 216 and early 235 engines are not "splash oilers" -- this is a splash oiler.