Mark 1 PX toolbox on a GP

I bought a genuine Piaggio one 6 years ago now. Only just got to hold it up to GP leggies. Looks like loads of cutting required to get this to fit.
Would I be better buying one that is already "moulded" to Lambretta leggies?
Would I be better buying one that is already "moulded" to Lambretta leggies?