I believe these were made by Johnson.  Can't find any info on them except some old info on a used one sold by Folk of the Wood some time back for around $750.  It comes with a nice hard case.  The tuners are Gotohs, the fretboard appears to be rosewood.  This is a round neck and it is pretty loud.  Nice deep tone.  There is some slight discoloration where the plating is coming off (looks like wear).  Remember, this is not a National, it's an import and priced accordingly.  Nut width is 1 and 11/16.

Pics here:

http://www.mandobar.com/sterling.htm

I am asking $600 with shipping to lower 48 states UPS ground.  Please no trades (trying to scale back).  Payment via US Postal Money order or Bank Cashiers check only.  Please e-mail me with any questions: myanocsk AT ix dot netcom dot com