Folk art? Salesman Sample? Mini Roll-top desk

I purchased this miniature roll-top desk on Ebay for $50 a couple of months ago. It measures approximately 10" tall x 14" wide. I'm not sure if it's a salesman sample or just an exemplary piece of folk art. The inside of the drawers are cigar box wood. The lock works, and the tambour door slides like a dream. As an extra bonus, the drawers remain locked unless the tambour is opened all the way. The open tambour triggers a system in the back of the desk that unlocks the drawers (see last photo above). I love it!! If anyone can provide any other info on this piece, it would be most appreciated.