I just discovered on my '78 Paramount that the Campagnolo skewer levers on the front and back wheels don't match. The one on the front is curved, the rear one is straight. Does anyone know which way it should be?

I think the straight one is period correct and the curved one came along later right?

Its borderline but yes, the curved were post CPSC or from '78 onwards. I suppose there's an outside chance your bike came with both. Open up your hubs and check the underside of the hub locknuts for date codes. '77 and older should be straight lever, '78 and newer should be curved. There's a little fuzziness in this area.

Depending on how Schwinn inventoried their supply you could have different hubs.