GATK4-beta Mutect2 input and samplenames

I'm using paired tumor-normal samples, and since the command line parameters have changes, I wanted to make sure that I'm defining my input files and sample names correctly. The command I use is

java -Xmx{params.xmx} Xms{params.xms} -jar {params.GATK} Mutect2 --reference {input.REF} --intervals {input.INTERVAL_LIST} --input {input.NORMAL_BAM} --input {input.TUMOR_BAM} --tumorSampleName {params.TUMOR_BAM_SAMPLE_NAME} O {output.VCF}

TUMOR_BAM_SAMPLE_NAME is the name of the sample as in the BAM header (SM). Is it necessary to define the sample name of the normal sample, when using paired samples?

From the help:
--input,-I:String. BAM/SAM/CRAM file containing reads This argument must be specified at least once. Required.
--tumorSampleName,-tumor:String. BAM sample name of tumor Required.
--normalSampleName,-normal:String. BAM sample name of tumor Default value: null.