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.
1984 Schwinn Paramount; 1987 Schwinn Paramount; 1975 Tom Ritchey, 198X Vitus