Mine do.

https://www.ford-trucks.com/user_gal...id=190136&.jpg

Not sure what you are showing in that picture, but if you are refering to the peanut shaped dish in the top of the piston, that isn't a valve relief, its the exit of the prechamber in the head.

I'll go and take some pics of the dimentions of the head, valves, and pistons so you can see what I'm talking about.

Not even the picture I thought I posted.
Now to find the right one.
I really need to organize my stuff better.

yup your right, not even close to being valve relief.:eek:

OK, this is the 6.9 piston:
https://www.ford-trucks.com/user_gal...id=194858&.jpg
The valves in the head:
https://www.ford-trucks.com/user_gal...id=194859&.jpg
And an example of a diesel piston that does have valve reliefs: (mitsubishi 2.3 turbo)
https://www.ford-trucks.com/user_gal...id=194860&.jpg

You can see that the smaller piston had a larger prechamber dish in the piston than the 6.9. I'm not sure how they could get away with this, but it might have something to do with the bosch VE pump that was used on those engines. Who knows, but but both engines seem to be capable of smoke free operation without any emission controls (with a turbo).