Chewbacca is shown in the prequals working closely with Jedi, and in EU spent a lot more time with them. I can't imagine that Chewie doesn't recognize the force as a real thing and know that Jedis are the real deal. But in ANH Han obviously does not put much stock in the force or Jedis.
“Hokey religions and ancient weapons are no match for a good blaster at your side, kid.”
But Han and Chewie have been close colleagues and friends for quite a while by then. How is it that Chewie has not shared his stories of his time with the Jedi enough that Han shows some evidence of knowing the Jedi are legit? Or how come Chewie doesn't rebut Han when he says the "Hokey religions" line? Is this just Lucas being bad at continuity or is there some retcon to explain it? Are Wookies just not much for sharing personal history? Is Han and Chewies relationship completely centered on the work they do together, maybe avoiding subject of "politics & religion" like people in real life?