HST's Hell's Angels Mentions Stencils (~1964)
(NOTE: The term "stencil" has been historically known to refer to screen printing images, rather than spray painting them. In the 1960s, stencils were put inside the screens and the image was made when the ink got pushed through by a squeegee)
"An Angel known as 'the Mute' was stopped by a policeman... . The Mute was proudly displaying his colors on a ragged Levi jacket. 'Take that off,' the patrolman [said]... . The Mute stripped off his Levi jacket, exposing another Angel decal on his leather jacket. 'Take that off too.'" The Mute took the jacket off, and then had a shirt with the emblam. The cop told him to take that off, and "under the shirt was an undershirt. It had been stenciled with the club insigia... . The Mute had the last laugh. He was prepared to go all the way. His trousers and shorts were also stenciled."
(excerpt from "Hell's Angels" by Hunter S. Thompson. This story was said to have happened sometime in 1964)