Scale and center 'label' attribute for prediction?

I need some help to set my input data correctly for a cross-validation task. I have only continuous numeric variables, and the label or target variable is also a continuous numeric variable.

I separate my data set into test and training sets, then train using a (neural network) operator. I have the Apply Model operator for the test set, and use the Performance operator for evaluation.

As my variables/attributes are output from different processes and have very different ranges, I need to scale them and I also centre them for use in ANN (SOM in particular requires this). Is it necessary to also scale and centre my label/target attribute?

(edit: simplified to remove a second question)