You have been dreaming! We didn't have the means to attack a P51 plus it was a fair bit faster than our 90 kt cruise, so chasing a P51 was not an option! On 2 occasions near the border, I had a P51 fly up my right hand side to formate! I think he may have had his flaps down! After a cheery wave he flashed off over the border. I certainly never heard your story either before my time or during.