Buggy,
The LCF emblem part numbers are as follows;
1956 Series 5, 7 & 9 3725794 Casting number is the same
1957 Series 5, 7 & 9 3738187 Casting number ???
The only difference between '56 and'57 is the paint colors, they share the same cast, so either one will work on your truck.
Have the seller lay the emblem flat on the table and if the top edge (the 6" wide section in the center) of the emblem is almost perfectly flat on the table it's for the LCF trucks. If it is raised up off of the table by about 1/4" in the very center it's a conventional emblem.
Hope this helps,
Mike B
