Ed Thomas question

In Michael Murphy's "Appalachian Dulcimer Book", which I saw for the first time this weekend on Geoff Black's stall at Launde (UK Nonsuch Dulcimer Club weekend), one page has two photos of an Ed Thomas dulcimer made in 1927 -front view and side view. (Page 26) The side view clearly shows that the fingerboard is raised (arched or scalloped). Since getting home from Launde, I've looked atL. Allen Smith's Catalogue of Pre-Revival Appalachian Dulcimers, and found that this instrument, which is in the Smithsonian, is listed and described there (dulcimer E9). There is no side view photo in Smith's book, so I'd not noticed this feature before.

The only Thomas instrument with an arched/scalloped fingerboard that I'd previously known about was one that belonged to the English folk song/music collector Peter Kennedy. He showed it to people at a "Meet Jean Ritchie" afternoon in Dursley (UK) in 1999. (Peter died a few years ago, and I don't know where the dulcimer is now.) Peter had had the instrument repaired by an English luthier in London some decades previously. I had always assumed that the arched fingerboard was an inappropriate restoration by that luthier, but the Smithsonian instrument makes me wonder if Ed Thomas did indeed sometimes use that design. Does anyone know, or is the Smithsonian one also an 'inappropriate restoration'?