Update:

I have uncovered a old catalog from CF Mountain, of course it is in Japanese .. not English...

I am convinced that my Mountain is a 300D. Wished there was a serial number list where I could make an exact match. My serial number is easily read and on the neck butt inside the body.   Also too, I have mapped the top bracing on this guitar and it matched the D35 Martin exactly. Only difference is the bridge width and thickness.

Here is the link to the CF Mountain catalog:   
http://www.t-shiga.com/sub1-6-25.htm

Would appreciate any other info…
Thanks