Yes, air filter elements should be replaced-about once a year or more often with a lot of rural miles. If your engine runs better without the filter its well past time for a new one. This is the same 37mm high element that fits single
HS2 carb or
HS2 twin carbs. The Cooper filter cannister that requires 2 filters was not quite so deep and therefore required the filter to be 37mm high as opposed to the original single which was 40mm high. For K&N elements see E-9001.
One rerquired for single
HS2 carb and 2 required for twin
HS2 carbs.