Yes. I think the basic brisket burnt ends are just that - burnt ends. You cut them off the brisket directly. They are cut off because they are burnt.
As I recall, Meathead talks about this, as it evolved a few decades ago. The pitmaster at an acclaimed bbq place in the midwest or maybe Texas would slice them off the brisket point muscle because they were considered dry and burnt. And, since they were considered "burnt", rather than throw them away, he'd throw them on a small dish at the bar for the customers for free. And people would nibble on them. But they were so amazingly delicious, due to the crispy rendered fat, they became a favorite.
Those were the original burnt ends which became popular. As Skinsfan1311 suggests above, they were salty, not sweet.
The idea of slicing brisket cubes and cooking them separate in a sweet bbq sauce is a different thing - even if they are called burnt ends.