The "bullet mirror" change out was very popular along with "Grant GT" steering wheels, "slot mags" or "Krager SS" rims, door and rear deck speakers, diamond tuck interior, "Hurst" shifters,"Gabrial Hi-Jackers", "Hooker Headers", "Moroso" chrome for under the hood and removing anything attached to the motor not needed for power. All added"improvements" for cruising town. Unfortunately a lot of the original parts went straight to the trash. Oh did I mention if you could afford paint and body work, adding rear fender flairs and removing those "hideous" factory stripes was a plus. And don't forget the "Isky" cam and "Holley" carb that came with endless adjustments and power valve changes.
I agree, my 68 SSRS 396 had the slotted mags and the 2ng gen bullet mirrors on it when I bought in in 02/'80. On top of that, I was one of those idiots removing most anything that didnt make it quicker in 1/4 mile.