There are 3 paths for you to select:
1. Absolute originality. Finding 4 NOS shocks dated for your car is close to impossible. Most people on this path watch for original shocks removed from another car and have them restored. Lots of competition for that, can get expensive [$1000+] quick. BTW fronts are easy [same as Nova], multi-leaf rears are not. I have never seen NOS rears in 35 years of the hobby.
2. Sort of original. Will look original to the casual observer but won't be dated correctly or have the exact part number. GM serviced '69 fronts into the late '80s under the OE part number but the shocks bore a different number. There are repro shocks but they are "for display only" I hear. There are similar appearing aftermarket shocks that can be painted to match originals. Rears again will be tough as most aftermarket units used a separate lower mounting stud. The OE shock had a pressed-in stud.
3. Don't care at all about originality. Any aftermarket unit will do. Best path for a car you intend to drive regularly.