My November of '69 SBD Challenger has the deluxe seat belt package.
I've seen cars that had both a 4 speed and the deluxe seat belt package, they have 2 light bezels on the dash, side by side near the ash tray. The reverse one is amber and the fasten belts one red.
As far as the Challenger script, I've see more than a few '70s with the plate rather than the script, but I've always assumed it was sloppy parts gathering during restoration, not that any were built that way.