Cracked decals sounds like a late '70s / early '80s model. They were notorious for that. Check the serial number on the headtube (below the oval Schwinn badge). The first two letters are the month/year codes. A=Jan, B=Feb (skip I and O) / A=1965, B=1966 (skip I and O again).
You can sometimes find decals on eBay or check with Memory Lane.
Not sure how unique the levers were to a particular year, but they used them on most all of the drop-bar road bikes for many years. Someone will have one for you -- post a WTB in the classifieds (for the decals as well).
Post pics!
Bob