I mean, it is a good point, and a data point however you feel about gun laws. The fact is, you can make a gun law, you can enforce the gun law, and it will have an effect. You can not like the effect, but it is a good datapoint that you can't say they never work. Sometimes yes, sometimes no.
Of course, in the argument-factory in the NRA, that just becomes "When there is 1 gun law, it is only a matter of time until your president is brought down through his son because of gun laws, or your super bowl hopes are dashed by the Gazpacho Police overzealously trampling your rights."