Absolutely. I would never let this end up in an estate sale or the like. I have already considered contacting a museum or university over some other things I have. And yes it was definitely a legitimate find and there is no way he would have kept it (or been allowed to as he was just a teen at the time on a professional dig) if it was illegal at the time.
Tell us about the other stuff! I love the strange stuff I've got even if it feels like a burden because I don't really know what to do with it. My prominent things that gather er dust are a left hand sword from the war of 1812 that has several nicks where it met other blades in life and death combat. A few other older pointy weapons from Europe and an old brass Scottish mining Lantern that's in mint condition.