Sway bar need?????

Comparing apples to oranges... the factory swaybar for pre 73 was smaller and weaker than 73 up. the early one also had triangle shaped forward mounts that hang a bit low and were subject to damage. The later type solved this by routing the larger bar through that K member. To keep your early K and add a swaybar to it, the aftermarket bars are a decent option. Most of those also use a end clip added on the lower shock bolt were you dont have those factory tabs welded on your lower arms.
If I didn't have the factroy parts I would add the Addco brand front bar kit.
Larger, stronger, more expensive brands may be overkill for some of us. Everyone has their own opinion of how one of these cars should feel and handle.