Yairi CY70 is a great guitar.I can fell the difference between the C9 in terms of build quality instantly.
Even though C9 is solid wood on top/back/sides and Cy70 is solid only on the top, the extra workmanship and skill on the Cy70 is plainly evident.
One thing I noticed is the action on the Yairi is a little high compared to C9, and no fret markers unlike the Cordoba.
I was so used to the fret markers.
May be action will be a little high by default on the classical guitars, not sure, but due to action being high on yairi than I am used to , and due to lack of fret markers, C9 makes it little easy to play in comparison I think.
Regarding the date, Alvarez asked me the same thing you said.But I could not find any numbers inside or outside.I examined the guitar thoroughly using a flashlight, nope,nothing anywhere.Not sure how to know the date on my guitar...