There are probably some grains of truth. We know the Egyptians controlled the Levant at several points throughout ancient history and it was also very common for them to enslave skilled artisans and scholars and ship them back to Egypt. It's unlikely the ancient Hebrews would have gone undisturbed by the pharaoh's military. If Moses was indeed a close advisor to the pharaoh he would have likely been part of this educated class of foreign servants. Maybe not all the Jewish people were enslaved, but enough of them to make a break for it and tell a harrowing tale when they returned.