Is this Normal?

Well, it certainly qualifies as a curiosity.

Wayne, I have this truck and all of the cases are printed in red.

@wayne,  I have also checked my truck and all the cases are in red.

I have a couple of black ones amongst a few spares I picked from somewhere I cant remember!

did you purchase this new or used? There are a few Coke themed models with black writing cases of Coke. If purchased used its possible the seller filled in a bare space with a case from another model.

@galen55 Well Galen55 you guessed it! Purchased used, along with several cars and trucks. With that batch, was a 1938 Coca-Cola Delivery Truck (MPN 907), and that truck came with 136 black painted Cola boxes! And look at the lower right of the picture, I added the missing one, and there is still one missing! CRAP! Haha

@geoff-jowett There must be a third delivery truck with black printing. On the ones you've showed, they have more printing on them, mine just say Coca-Cola.

@wayne the mystery deepens! I have the Model A, 1927 Ford, and 1928 International trucks which all came with Coke bottles but unfortunately they are all packed away at present so I cant tell which bottles have come from which trucks, plus I do have those extras.

@geoff-jowett Here's the two you have, and they are both the red cases.

1927

1928

hmm curiouser and curiourser!

@geoff-jowett Looks like your extra black printed cases came from the 1931 Panel Delivery Truck.

Excellent Wayne. As mentioned that model is unfortunately stacked away at present so I couldn't check it. Did u notice the Coke truck Galen posted the other day? Looks good for an Ertl. Couldn't find one on ebay though.