Yes, early humans were likely carrion feeders among other dietary strategies. Archaeological and anthropological evidence suggests that before developing tools and techniques for hunting, early hominins would have scavenged carcasses left by predators. This behavior would have allowed them to access a high-quality source of nutrients like protein and fat, which are crucial for brain development.

The use of tools made from stones to break open bones for marrow and to possibly butcher animals suggests that early humans exploited carcasses that they found or scavenged from other predators' kills. Marrow and brain tissue, which could be accessed by breaking open bones and skulls, are highly nutritious and would have been valuable food sources for early humans.

Over time, as hominins developed more sophisticated tools and techniques, they likely became more efficient hunters, gradually shifting from scavenging to actively hunting for their food. However, the practice of scavenging would have played a critical role in the dietary habits of early human ancestors and contributed to their evolutionary success.

https://academic.oup.com/bioscience/article/64/5/394/2754213