This guitar is one of the first batch of Deluxe, Dual Professional and Custom family of guitars. Per exchanges with Jody Carver (and his info from Don Randell) back in 2003, he surmised there were about 55 or so (total of all variations) made in the 1947-48 time frame. They had the rectangular ‘BoxCar’ pickups and Roman Numeral fret boards. As most already know, no exact serial number/inventory records are known to exist and they weren’t chronologically sequential. Below are my pics & others as noted & the anecdotal info is from searches on this Forum.
(ref http://steelguitarforum.com/Forum2/HTML/003692.html)
My guitar has no leg sockets. They were an option.


and has a unique ‘well’ tag...

(Also, there was a pic & reference that some of these early three-neck Customs also had this same “Dual Professional” tag.)
Has a ‘Big D’ serial number...

Here’s a pic of the Princeton lap steel with RN frets...

And lastly a pic of the late Rick Alexander’s Dual Professional...

Most were the darker (walnut?) wood & the lighter/blonde ones (optional cost) were either ash or swamp ash.
Again, this was the info I found from searches on this Forum & may not be accurate – just my musings & understanding at this point in time.
Bottomline, I would like to secure a pair of these RN fret boards for my early Dual Pro.
Thank you to b0b & all the supporters/contributors of this Forum.
Regards, John Hanusch