It looks like 8 of 21 to me as well. #1,4,7,13,15,17,20 & 21
Picture is bad but I see 7 silvers clearly with the 8th being tarnished, but the ones that look like regular clads could be well worn casino halves, so they all could very well be 40%'s but it's really hard to tell from your pic.
My guess is that you woulden't be asking if they werent all keepers. The ears would pick up on the silver if you drop them from one hand to the other. If your still not sure, you could always look at the dates.... lol
Again, my apologies on the bad picture. Releasing the answer is killing me so I'll tell now.
I just wanted to show some newbies out there that casino silvers look like clad. since i do the drop test on every roll i caught ~ 10 that would've slipped through.
good job silver stripe and right on the mark with your comments mojo. HH all.
if anyone has a better camera post a pic of casino silver next to casino clad.