I ran the recon-all command and got all the .label files for the segmentations of the cortical areas. However, I have some questions about the label for primary motor and auditory cortex. 

• I found two types of labels associated with the primary motor cortex: lh.L_M1.label and lh.BA4a_exvivo.label. Are they both valid, and the lh.BA4a_exvivo.label segmentations are finer parcellation than the other one?
• What's the primary auditory cortex .label file?

Thanks in advance!