Originally Posted by Metacortex

That confirms this as a late '74 bike. Note that those rims will have date codes next to the valve stem holes on the inside of the rim, here is an example of the very same Weinmann hooked bead rims dated 9-74:



The hubs will also have date codes, and likely so will the Atom 440 pedals. Schwinn (and its suppliers) began date coding more and more components around that time. By 1976 most of the components on Schwinn bikes were date coded, including the entire bike itself by virtue of the headbadge.