7 day streak guarantee upgrade items?
There have been talks about receiving upgrade items from spinning pokestops. I received a dragon scale from spinning stops regularly yesterday (it was not my 6 streak spin) today I received the metal coat for the 7 day streak spin.
So the question is, does the 7 day streak guarantees an upgrade item?
Can someone else confirm for their 7 day spin.

Answers
Just mere luck. Today was my 7th and I got nothing.
Edit: I rechecked my inventory since I saw I am the only one who said "I got nothing" and I saw this. My bad. I probably didn't see since I was driving earlier during my 1st spin of the day. I haven't tried spinning other stops today after that. That I'm sure so I can guarantee this evolution item is fresh.
I also got my first evolution item, a Porygon "Upgrade" today from the 7-day streak.
I don't know whether you are guaranteed to get an evolution item from the 7 day streak bonus, but I guess that the chance that you receive an evolution item is somewhat higher for daily streak bonuses and immensely high for the 7-day streak bonus.
The base evolution item drop rate appears to be VERY small
I confirm that I got a King's rock with my 7th spin. It was also a pokestop beside the river where slowpoke spawns frequently (just to add speculation).
My other 2 evolution items came from normal spins.
As long as there are reports of people not getting it in their 7th spin we can't really say that is guaranteed. What we may say for now is that we have better odds to get it from the 7th spin. With such a large pool of items coming from the one pokestop it is likely that the odds increase