My understanding is, and I may have read it in Bunn or just made it up myself, that after 1950 the hood ornaments were an option installed by the dealer. Those old enough to remember or who just paid attention in history class will know the Korean conflict (i.e., "police action") started in June 1950. Thereafter, and for several years, the auto industry "adjusted" to government mandates regarding production. Things like chrome and aluminum were in short supply. I suspect, although I don't know for sure, that the hood ornament as standard equipment went the way of the dodo bird...
As an aside, I prefer a "naked" hood on the 51-53 trucks because the grill is already pretty "busy" and the hood ornament just "gets in the way..."