The ozone light in dryers seemed to appear fairly early on - possibly as early as the late 1940s. I don't know if it's the ozone light or the drying system, but clothes dried in an older Frigidaire Filtrator dryer smell wonderful! I'd better be careful or I'm going to wear out my '51 Frigidaire dryer, I use it that much... LOL
I have the ozone lights in the 1956 Whirlpool and the 1966 Inglis dryers, but the '65 Lady Kenmore (which, thank goodness, still works...LOL) no longer had one. Likewise, the '56 Whirlpool washer and '66 Inglis washers have an ozone tub light. It just looks cool...