Looks like it's the maculatus, thanks. The argenteus look similar, but their sides are completely blank- mine have spots, and their spots are showing up more as they settle in.
And holy cow, these guys SUCK at eating. Mine are all about the size of an actual silver dollar, and since I got them yesterday, I just fed them for the first time today- bloodworms. They had trouble eating the bloodworms. Granted, the bloodworms are fat and curled into circles, but my glowlights tackle them with no real problems.
Yes, I know silver dollars need plenty of veggies. Bloodworms are my default food for new fish, as the scent often coaxes them into eating, and these guys definitely liked the scent.