Hi Andy,
Very cool find! Hopefully it is also free of mildew and mold since it was just in storage. Yes, they only fetch less than $500 used these days, but factoring the amount of work to get them working, repaired, and tuned is many hours or usually costly. I spent 5 hours just fine tuning and gapping the reeds! I would suggest contacting Bill Morris for any repair work/modifications you might want. Cut plates that have screws are a major plus in my book. I’m also guessing that, “Tate,” engraved on the plate might not be anything significant even if it was owned by Douglas Tate for its value.
The chord harmonica kind of relates to the rhythm guitar in a rock band so there’s another cool thing. Players like Wally Peterman, AJ Windmeyer, Bud Boblink, and Al Smith are four top notch living chord players in the US off of the top of my head. You can see their videos for inspiration like I have. I play chord, too, and I’m enjoying the journey of getting better and discovering new things about it.
Btw, I know Puleo is a somewhat common last name but any relation to Johnny Puleo of the Harmonica Gang or Harmonica Rascals bands?