these are the kind of builds i love to do, like "period correct-ish" but with some nice upgrades that are a little more modern and contemporary.
the best that was available in 69 gets absolutely out shined by a whole host of stuff that's now available and wouldn't change the overall look of the car one bit: better t-bars, springs, sway bars, shocks, tires(!!), wider rims, better brakes, electronic ignion, etc etc etc; but would change the feel of the car in terms of functionality, driveability, ease of maintenance while retaining all of the old school charm.
so yeah, those discs were an option. and if you want to stay small bolt, then that's what you should run.