All I found was this old listing on Reverb:

https://reverb.com/item/6939411-music-crafts-mountain-music-dulcimer-4 string-vintage

It probably looks like yours.  No date given, but the same labeling.

I've done a bit of looking in Jean Ritchie's Dulcimer People and not found a maker working under that label name. 

No date or anything else.  Mysterious!

Is there, by any chance, a date on the label?  

I bought a used Dulcimer and can't find out anything about it on google or this group search.  Inside it says:

The Original Mountain Music Dulcimer, Another hand crafted product of MUSIC CRAFTS of California, Los Gatos, CA 95030