To Guitaaress,   Shame on you , you didn't do your homework therefore you are commenting on something you shoudn't because you lack information. No worries, we will educate you. There were Sigma models made at the Nazareth plant. The DR-28N and the DR-35N are 2 of them. The N suffix tells us this. Taylor, Santa Cruz and Collings are good instuments but not everyone can afford them Your comment on the Sigma brand..."they are excellent value if carefully chosen as the quality varies greatly"....applies to ANY mass produced brand at any price point. Tonal deficiencies appear at ALL prices, I own and have owned and played/recorded Martins and Taylors. My Japanese DR-7 competed with these guitars on many occasions and performed very competently.
I have read this thread from top to bottom and I have yet to read a post stating these intruments were renuine Martins.
What I have read is that there are many owners that tested their Sigmas agaainst the big dollar brands and couldn't justify the huge difference in cash for, at times a minimal gain in performance.
Your 76 tour to Martin enforces the claim that all Sigmas were setup and inspected in Nazareth before being delivered to the dealers. Thank you for that.
Please don't be a "brand snob", spend some time reading this thread.
You will learn a lot.

Neil