did they have a shoulder seat belt for the driver and passenger side?

Yes - Actually, front seat shoulder belts have been mandatory on US passenger cars since 1966. - OK, not quite accurate, although it does get a bit confusing. It goes ROUGHLY like this: 1964 - Front lap belts. 1966 - Rear lap belts. 1966 - MOUNTING for front shoulder belts, although the belts were optional. 1968 - Front shoulder belts. Somewhere along the line center seat belts became mandatory for larger cars, and later came rear shoulder belts. Now, that is all related to passenger cars. Trucks had different dates. If you are really, really bored, you can search this more on the net :)

** January 1-1968** > As per State Police Vehicle Safety Inspection manual.. Don't know about what's on the Internet!