I think it's time to ask, "Is there such a thing as a Welsh harp or an Irish harp?" at the time in question.

Given the small number of people who play harp at any given time and the small number of who can afford to stay in business, harp makers may have sold their individual models to whomever would buy them. A Welsh player might have bought from an Irish maker, or a Scottish player from a French maker, et cetera.

Remember that none of these regions are very far apart.

Kate, you might see if the Shrine to Music Museum in Vermillion, South Dakota will talk to you.