IT APPEARS that the people who make and market spray paints could use some instruction from the personal armaments lobby. Representatives of the paint industry failed last week to fend off government interference when a New York City anti-graffiti bill became law. It requires stores to keep their spray paints behind the counter (to prevent shoplifting) and forbids their sale to persons under 18.

Representatives of the industry made the expected arguments about the harm that would be done to merchants and the danger of creating a black market in spray paint. Then Mayor Edward Koch went ahead and signed the bill in the hope it would have some effect before every surface in the city was decorated with a Day-Glo message.

As the gun lobby could have told the paint people, that's not the way to go about it. What you do is, first, invoke high constitutional principle. In this case, the First Amendment, with its free-speech protections, comes to mind as clearly being meant to include the right to bear aerosols and to express oneself by means of foot-high fuchsia script on the side of a subway car.

Next, inspire thousands of letters of protest from the sporting branch of the spray-paint community. The sports involved here are primarily fence-climbing, petit larceny and sprints. Distribute bumper stickers that say, "I'm a recreational spray-painter, and I vote."

Finally, organize a public relations campaign by enthusiasts, perhaps united into some organization on the order of Protect Our Right to Spray-Paint. Ads with the theme "We're the PORSP" would show a variety of respectable people spraying tasteful shades of lacquer enamel on such things as wicker bassinets and porch railings. ("Mayor Koch," one of them would be saying, "do I look like the sort of person who'd climb a chain-link fence to paint my name on every bus in the maintenance depot?")

The spray-paint industry might well be skeptical. Surely, it would say, no serious branch of government could be persuaded by this sort of thing. To which the gun lobby could reply: "Wanna bet?"