Looking for info Cox Fireball P-51 Mustang

I have picked one up at a yard sale and in my google searches the PAT was issued 1976 -returned 1978. What it doesn't say is What month it was processed. I opened up the inside to find the Make Date stamped on the plane which is April 26, 1976.
I'm hoping some one on here has more information then what I can find in google
April is early in the year, I believe it may be the first or one of the first assemblies of this model

Greetings and welcome to the forum.
I've not heard of a "fireball" P51, by Cox. According to Martin Hepperle's web site, there have been over 12 variations of the P51 from 1963 to 1991
There's been the Fighter, Bendex Racer, Avion, Miss America, Sweet Cindy, Invasion, Red Baron, and Miss America again.
You are too new to have picture posting ability, but pictures would be nice to help identify your model.
Follow the linc under the "Instruction sheets" on the left hand margin  of this web page
And go to the model data base:   http://www.mh-aerotools.de/airfoils/cox_frameset.htm

And search for your model. Good luck and have fun....post some pictures when you can!