I believe it was a prototype?
More info from the web;
"This is a tricone ukulele made by National in 1927. Unique and rare design. This was from Andy Griffith's collection, he used to play it once in awhile in the "Matlock" TV series".
Thanks for that. Interesting-looking instrument.
If you want to see a good movie starring Andy, look for "A Face in the Crowd." Not very funny, but a good, realistic story.
Get one for yourself - with free shipping!