I'm not sure there's an easy answer to this.

The initial production run had breaks in the splines between the groves on the pulley and looked like this:


Those breaks were supposed to give better grip on the belt, but ended up either chewing up the belt or giving less grip - I can't remember which now. Also the initial run was aluminum. Later they were switched to steel as there were some manufacturing problems with the aluminum pulleys.

The later pulleys look like this:


Of the later pulleys, there are two sizes: the original and the mid-sized. The original was designed to closely match the performance of the 178mm crank pulley, but it turns out to be a little less performance. The mid-sized pulley is sized a little larger than the original, so that it can safely be combined with a 178mm crank pulley and not overdrive the supercharger beyond design specs.

The stock supercharger pulley is 74mm.
The original Code3 SC pulley is 65mm.
The mid-sized Code3 SC pulley is 69mm.

Visually it is difficult to tell the difference between the mid-sized and original Code3 pulleys.