The second guitar I bought also off Craig's List is an FG-75. It too is a Red Label, Nippon Gakki, Made in Japan guitar.
It took me a week to arrange a time to meet with the seller after confirming the width measurement of the lower bout. I had the same reaction from this guitar. Tons of volume, sustain, and good rich sound.
I couldn't believe that I had found 2 of these guitars that had straight necks, and no need for a reset, with very low action. I might even need to raise it a little to play slide on them.
Here are the specs on the FG-75:
Upper Bout - 11-1/8"
Waist - 9-5/8"
Lower Bout - 14-5/8"
Depth at tail - 4"
Depth at neck - 3-3/4"
Body Length - 19- 1/8"
Total Length - 39-1/8"
14 frets to the body
From Yamaha's database:
Year(s) Sold: 1968-1974
Original MSRP(US$): $109.50
Top: Spruce
Back / Sides: Agathis
Neck: Nato
Fingerboard: Indian Rosewood
Bridge: N/A
Notes: Folk Guitar Classic Type
EDIT: The FG-75 uses ladder bracing with longitudinal braces on the sides of the sound hole.
The serial number on this one worked in the Yamaha serial number wizard, and shows it to have been made on January 28th, 1972. It will turn 40 years old next month.
They are both beautiful guitars, and I am very pleased to have found them.
Here are pictures of the FG-75, and one shot at the end of them both together.
I included a shot of the serial number just under the edge of the sound hole, but wondered if it was possible that this one had a signature as well. The little circle in that shot may be a signature in the form of a "chop" rather than a hand written signature. Those with more knowledge can let me know.