Kit built dulcimer?

I've recently acquired the dulcimer below. I saw a similiar one on ebay and the seller pointed me onto the Hobgoblin site where there are two more. The "burnt in" fingerboard decoration is unique to mine, which also has, of all things, a perspex nut and saddle, though the others are bone. It had an an "accident" and the top fell off, revealing that the inside faces were printed with things like "top inside" and "left side". There is no makers label. Given that there seems to be a few of these about plus what is printed inside, my theory is that they were commercially made in kit form, maybe early- mid 70s? Two of other ones have makers names, though they may be the assemblers rather than the actual makers. Anyone else got or seen one, or any adverts for them in the folk music press of the time? The radiator is off, by the way!

Grahame