They do, like War Nickels. It is the Manganese they put in the alloy. There isn't much in it, but I guess they used it for the electromagnetic signature it gives to match the SBA copper-nickel alloy.
A girl at my local bank keeps them for me. My granddaughter likes them and I thought someday I would leave her a sack-of-gawea's.
I used one for scale when photographing an unusual spider that was in the process of eating a Japanese Beetle, but don't have any in my collection. The design IMO is far better than that of the SBA.
I like em because they have the no date obverse varieties and all of the different reverse themes, which a lot of folks don't even know about. Compare that to it's predecessor the SBA dollar coin, where the only variety is an indistinguishable mint mark serif and a similarly unremarkable rim size difference.
that's the same reason I like the Proof Platinum Eagles .. different Reverse themes. Though they cost a little more.
I just got these today. They're for a kid we watch when his Mom is at work on the nights the BlackHawks play. I watch the game with him and started him on affordable collections. For that ... LOL ... I drink free at the bar where she works. first:
HAVE (10) 5 coin sets Pr. 70 & 6o"s position A& B in Velvet display boxes, look pretty nice. Also the coin and currency sets ( certified dollar and coin )