Ralley Green Z at MCACN

[68 Ragtop]

You would think the owner would know there were more that 20,000 Z/28's made in 1969 and used the actual number in the poster board to gain more credibility, instead of a round about number.
I also think he is trying to say it is the only known real Z/28 with an X11 trim code, and in addition it happens to have a special casting date of "M". I am assuming the stamped codes are all legit. It looks like he is quoting Jerry M. on the poster, but can't read it. Anyone know what it says?

[SMKZ28]

Here's the pictures I took of the car and the sign at 2017 MCACN.  The quote says, "This is the first time we have ever inspected a Z28 with an X code error," Jerry MacNeish.