No AMA requirement for the fire extinguisher except for the Jets.

It is highly recommended for people with gasoline power models to have an appropriate fire extinguisher.

Glow models VERY rarely catch fire. It was more common (but still rare) for glow models to catch fire when mufflers weren't used a lot. Priming via squirting some fuel in the exhaust could light the thing on fire. (usually you could just blow it out like a candle... no harm=no foul=not ever reported. I lit a few up that way.)