Dean was looking to Sam as he put Bobby on speaker, wondering what was going on that Sam did this. There was a scoffed sound from the other line that made Dean raise a brow in suspicion. 

"Boy, then I suggest you tell that to him. You should know that such things have truth to legends and myth. From what I understand there is a record of the Van Helsing and their family tree recorded but some of that was lost and only pieces remain. Hence the books." Bobby explained.   

It was Dean who chimed in. "So wait. You're saying that these Van Helsings were actually real and turned to fiction characters. Wouldn't they be the first Hunters in existence?" Dean asked.

"You got it. The very first." Boddy confirmed. "Now. Here's what I want to know. Are you thinking these two mystery individuals you ran into are part of that family?" Having connected the dots to Sam's questions. Dean looked to Sam on this.