I am sure you will get a more knowledgeable answer in this forum,� but I can help a little by looking at my '51� (dented and rusted, but mostly unmolested)
- mine does not have the 3 holes at bottom-front or the 4 holes on bottom of grill.
- mine has 3 encapsulated nuts per side. (yours appears to be missing the ones at the top)
edit:� athawk is going to force me to go out in rain and look again.� I did not see any holes on the bottom in the first quick look.� (to clarify, athawk did not force me,� my curiosity did�

)
edit2:� as I was certain - >� athawk was correct�

,� there are 4 holes on bottom of grille on mine (but filled with bolts),� they are holding a shield that would keep stuff from getting sucked up between the grille and crossmember -> into radiator.� . .� �if you would like photos of my rusty one,� let me know.