This is only one of two instances where Bruce Lee is seen using a gun in his entire acting career, even though the gun fired blanks. The only other time Lee used a gun in a film was in Marlowe (1969).
The original air date of this episode is disputed. The very same sources that report The Hornet and the Firefly (1967) aired on December 30, 1966 rather than on March 24, 1967 (with December 30 skipped), also switch this with the following week's Ace in the Hole (1967).
This is the only episode where Kato removes his mask. He does this while driving.