Well if you go to the Happy Donkey website they sell just a single domestic Gaggia PF and a commercial PF so I guess one fits all domestic machines. it might be worth asking one of the shops (happy donkey or coffeeHit or someone) just to be sure.

 

I'm pretty sure they are all the same. My TS has a more commercial PF which means its just more solid and heavier.

 

I am pretty sure that on the Pure and Classic the portafilters are in fact exactly the same except that the Pure has plastic spouts compared to the Classic's metal. However, this difference would not affect the fit with the machine.