Here's the way I understand it:
'53 & '54 Jubilee/NAA: gray grille with thin vertical fins and a round crank hole at the bottom.
'55-'57 600/800: Same as NAA grille except the crank hole is oval.
'58-'62 601: same as the 600/800.
'58-'62 801: red square grid grille
The rowcrop tractors (700/900 and 701/901) follow the same trend as the 600/800 and 601/801 except I think the grilles on those tractors are not as tall....I could be wrong on that.
That's the way I understand it. I'm open for correction if I'm mis-stating the facts.