Was there a difference in the primary deity worshipped by Balaram Dhurandhar compared to his father?

Yes, there was a difference in their primary focus of devotion, although the entire family was deeply religious. Chapter 51 explicitly states that while the family had a strong faith in Shri Rama, there was a distinction between father and son. The text mentions, 'the father's deity was Rama, while the son's refuge was Vithala.' This indicates that Balaram's father was a devotee of Rama. Balaram, on the other hand, was a devotee of Vithala of Pandharpur, also known as Panduranga. His deep connection to Vithala is further emphasized by the statement that upon his death, he 'merged into Vithala.'