Honda never offered a rear rack and those had "CT70" stamped into the tubing, as well. Back in the early `70s, the local Honda dealership had the racks and made no bones about them being aftermarket. As for a sissy bar, can't imagine Honda wanting to step into a liability snake pit that big...not even 40 years ago.
None of this has anything to do with the quality of the parts. They're just not OEM equipment. If you like, `em, use `em.:4: