[Roadsters] Cam bolt

[L J]

Hello List,
Has anyone ever had the cam bolt back out with also the cam key being disrupted? I had this happen recently, the cam gear was loose, the key was upright and of course the car had lost all power. 
The car is back together now with no apparent harm, I guess because of the non interfence 1600 engine. I also know that there are SAE and metric cams and the bolts are different. Would a SAE bolt thread into a metric cam and vice versa? If so I could see it coming loose. I have a 69 1600 motor but did not think to check thread pitch. It is in there tight with also some blue thread locker on the threads, and the cam key is glued in also now.

Linda