As BR says, the Class 1 is valid for Class 2 privileges and validity periods (it actually says that on the certificate).
It doesn't cost much more to renew a Class 1 against re-validating a Class 2 , so you may want to think about keeping it going in case you have second thoughts about a CPL.
I believe that you need to re-do the initial Class 1 if it hasn't been renewed for a certain time (10 years?).