Shaft Question: True Temper Dynamic 7765C

[Pollie017]

Our office has a hitting bay in the basement with an assortment of old clubs.  I found a Power Built Citation 2iron with a TTD 7765C shaft.  I tried it out and was striping the ball.  I'm going to get it regripped and try it on Trackman tonight.  My question.....

What type of shaft/flex is the TTD 7765C?  It feels very solid, but based on the age of the club, I doubt it's a X flex.

Thanks in advance.