1969 Barracuda door glass

I just went through tis with my'67 fb Barracuda. The side glass is tempered and harder than the windshield glass making it more difficult to polish. Know from spending hours on my side glass that found a new home at the landfill. It's worth the money to buy new, if it's available. I bought mine from Classic Industries. They currently do not show any for notchbacks. I would try Metro.
Classic Auto Glass - Windshield Glass, Back Glass, Door Glass, Vent Window Glass and Quarter Window Glass - Plymouth Barracuda, 1964, 1965,1966, 1967, 1968, 1969, 64, 65, 66, 67, 68, 69 - Catalog Product List Page

The big problem is there appears to be only one manufacture currently producing glass for our cars and they have stopped production of some products (green tinted rear window Fb) and are not going to start again in the near future. I have called and spoken to Sanders Repo Glass, Metro and Auto City Classic when I was searching for new rear window glass for my Fb. I ended up buying used from Wildcat auto wreckers in Oregon, it may be worth the drive from Utah. Luckily, they had about twenty of the, I cleaned fifteen windows before I found one that was "almost" scratch free. Hope this helps.