Make mine a Dr. Pepper, please.

My final grins and giggles. All this work has made me thirsty. Speaking of which, wasn’t Oswald’s preferred beverage a

Dr. Pepper?

 I'm not saying Coke and Dr. Pepper were the only two beverages available to the workers at the Texas School Book Depository, so this analysis has plenty of room for doubt. However, I did study the distinctive shapes and labels of both Coke and Dr. Pepper bottles from the 1963 era. The above seems viable to me.