I agree with the others -- a Hughes Church Dulcimer kit. The second dulcimer I built 40 years ago.
Replacing the Nut & Bridge should be straightforward as long as they aren't glued. If the Nut is glued, try heating it up with a heat gun or hair dryer on High for 10 minutes or so. That softens Titebond and Elmers glues. If all else fails you can cut them off and sand them down flat before making new ones from some of the scrap maple from your recent build, to sit on top.
As mentioned, the tuners could use at least a good cleaning. They weren't all that great of quality back in the day though... If they are, as I suspect, 3 tuners on a bar, you can get a replacement pair for about $10 from Stew Mac (I just checked the price).
updated by @ken-hulme: 07/17/19 09:28:31PM